Diagonal Cut

""Aaaand, the split... Any minute now. Damn that must have been a smooth cut, he ain't falling... apart.""

- Dr. McNinja, The Adventures of Dr. McNinja

A swordsman strikes an opponent or other object with a mighty blow, almost always on a diagonal -- from shoulder to opposite hip if the target is human(oid). For a moment, nothing appears to happen. A few seconds later, though, the top half of the object begins to slide off the bottom half: through great strength, great skill, the legendary virtues of the sword, or a healthy dose of Applied Phlebotinum, the sword has neatly cloven the object in two with a single blow. If the cloven object is a person, they may laugh for a moment before a shocked realization and then slide apart.

Disconcertingly, the actual depth of the object that's being sliced never affects the outcome of this move. It's possible to Diagonal Cut items that greatly exceed the length of the swordsman's blade, such as cars, sequoias or in extreme cases entire buildings.

A variety of Clean Cut, and compare Single Stroke Battle; this is a slightly more over-the-top version, and applies to inanimate scenery, too. Razor Floss tend to deliver Diagonal Cut once per show for extra shock value and/or bonus awesomeness, then Clean Cut is toned down back to more believable forms.

Bonus points if nothing happens until the sword is resheathed.

In real life, it is possible to accomplish this on humans, albeit without the dramatic delay before the target falls apart or the amazingly clean cuts that are seen in the movies (at least on most targets). Its also rare for targets to be cut straight through -- armor and bones are harder to cleave through than flesh. In fact, in iaido, the diagonal cut (kesa giri) is one of the basic strokes, where the intention is indeed to cut from the shoulder to the opposite hip, and at more advanced levels, practitioners actually practice doing this to rolled up tatami mats and other inanimate objects.

Incidentally, a recent survey of battlefield grave sites in Japan, analyzing skeletons for cause of death, found kesa-giri to be the most common by far. There were hardly any examples of fatalities from a straight downward slash (the favoured move in Kendo).

In European swordfighting, this (the Zornhau, or "wrath hew") is also one of the basic strokes. And European battlefield casualties from Medieval times do indeed, just like the Japanese example above, show the same kind of injuries. Which is easy to explain, since the head, pretty hard by itself, was the first thing to be covered with armor, so shoulders provided the only bodypart to aim at with overhead swings.

All Japanese swords are supposed to be able to do this. Historically, a swordsmith could only become licensed if a swordsman could perform this cut on a dead body with a sword forged by that smith. (Or on a condemned criminal. Nice guys, those feudal Japanese.)

On a practical level, most swords are slashing weapons. Sure you can stab a guy with one, but during the eras when swords were the in-thing, you normally wouldn't want to. There are rather fewer ways of stabbing someone to death than you might think, and it only gets worse when that someone is armored and fighting back. Stabbing also very heavily commits you to attacking while well aimed slashing turns into blocking rather easily. It wasn't until gunpowder was all the rage and armor became pointless that foot-fighting swords became slim and stabby. A well-wielded rapier can beat just about any other blade because its fast enough to avoid being blocked, but that's only helpful if there is an abundance of easily accessible fleshy bits to stick it in.

Historically speaking, if you want to stab people, you want to get yourself a spear of some sort. The range involved means you can stab a bunch of times with a lot of force while the other guy is too far away to do anything about it. The only armies that relied on stabbing with swords (and even then not on swords as a primary weapon) were the Spartans and Romans, the notable parallel between them being large shields, all over armor, very short swords and total disinterest in fighting fair. Accurately stabbing someone in the heat of battle is a lot more plausible when you've just concussed him with your shield.

Someone has cut together a reel of many notable examples of the diagonal cut. Be warned, however, 4 minutes of people getting sliced up, even in Hollywood-improbable circumstances, can be a little unsettling. However, it may also be a hilarious example of how this trope should probably be limited to animation. Further, it shows that something used too often can lose its effect very quickly.

Anime & Manga

 * Mikoto's sword Miroku in Mai-HiME.
 * Likewise, almost all Otome in Mai-Otome who use swords as weapons.
 * Vision of Escaflowne
 * Maze Megaburst Space
 * Sailor Moon
 * Kunô does this to a tree with a bokken (wooden practice sword) in an early episode of Ranma One Half.
 * Lupin III, Goemon does this frequently. Things rarely fall apart until he has resheathed his sword, and at some point he will say, "Once again I have cut a worthless object."
 * This is how Kagato is defeated in the Tenchi Muyo OVAs. Tenchi himself suffers a similar cut in the exchange with Kagato, but is so charged with power that it heals instantly. Kagato's own previously-established Healing Factor, on the other hand, was negated by the sheer power of Tenchi's literal Infinity Plus One Sword. Also, rather than the halves of his body sliding apart, Kagato disintegrates after a few seconds, giving him enough time to congratulate Tenchi on his victory. Of course, it's only after the girls show up that they realize he also Diagonally Cut the whole space fortress. Which was in some unexplained way linked to Kagato's body.
 * Digimon Adventure has WarGreymon taking on the giant mecha dragon Machinedramon. WarGreymon rushes forward with his Dramon Destroyer claws swinging wildly, Flash Steps to behind Machinedramon, and de-digivolves to Koromon with a cut on his own forehead. Machinedramon appears untouched and turns to boast about the heroes' apparent loss, only for Koromon to reveal that during the charge Machinedramon had been sliced "like an onion." Machinedramon's body then collapses into three clean-cut pieces -- a great scene and a fitting end to a huge Jerkass with a very real Kill Em All attitude.
 * Dragonball
 * Yajirobe's fight against Cymbal. Yajirobe quickly draws his sword, slashes, and resheathes it. Cymbal starts laughing when suddenly his upper half slides off his body.
 * (Future) Trunks does this to Frieza in Dragon Ball Z, although it is a vertical slice instead of diagonal, and after Frieza slides apart, Trunks then slices those two halves into about a dozen smaller ones before blowing them away. Amusingly, the camera briefly shifts to Frieza's point of view just after he's cut in half, with the screen splitting in half as he is.
 * In the seventh movie, Future Trunks battles Android 14, their fight comes to an end when their blows collide with Trunks using his sword, Android 14 comes out seemingly unscathed he runs out at Trunks and his body splits in half just before he reaches him.
 * In the manga and anime Samurai Deeper Kyo, when Kyo is just about to end the battle and waste the other guy, all he does is one slash. Then he sheathes his sword, tells everyone to haul ass because they need to get to wherever they're going, and starts walking away. Then the enemy tries to move and slides in two. (It's more vertical usually but it's still along the lines of a Single Stroke Battle.) At one point you don't even see him move. Not even any movement lines. Just his sword clicking as he puts it away.
 * Claymore is a very festival of Diagonal Cuts and Single Stroke Battles.
 * Rurouni Kenshin
 * Even though the protagonist is a Technical Pacifist during the series, he vanquishes several inanimate objects this way. At one point, he uses his Diagonal Cut to slice a vegetable... which he then is able to stick back together because the cut was just that clean, as a proof of the blade's sharpness. His style, Hiten Mitsurugi Ryu, even has a name for this technique. He actually did this using a KITCHEN KNIFE, rather than his own sword, although it was to test the quality of a prospective sword supplier's work.
 * Used in the movie version, in which a character is shown partially unsheathing his sword, there is a flash, and then a confused-looking sailor takes a drink from the bottle of wine he is holding, which falls in half minutes later. yes, minutes.
 * One Piece
 * Any and all fights in which Zoro takes part will feature this trope to excess. Most notably when he sliced through the Sea Train wagon during the Enies Lobby arc.
 * In the battle against Don Krieg, Mihawk slices Krieg's entire ship in half like this. While Mihawk's sword is big, but not that big; he has some as yet unexplained (and given the nature of the series, it probably never will be) ability to slice through things without his blade actually have to touch them.
 * During the Marineford battle, he actually slices through a frozen tsunami. Why? He tried to slash Luffy and missed.
 * Brook manages this a few times during the Thriller Bark arc.
 * In an episode of Super Robot Monkey Team Hyperforce Go, Nova does this to a tree. Which is odd considering her usual choice weapon is her own fists.
 * Done to high-rise apartment building in Kaze no Stigma. Everything else starts out with such a cut but quickly gets diced in the follow up.
 * Get Backers: Kuro(u)do(u) Akabane frequently slices victims -- sometimes like this, sometimes far more elaborately, sometimes several at once -- and they don't realize it until long after he's finished, come to a stop, and said something to another character. Then Ludicrous Gibs occur almost explosively. If you see Akabane, and then suddenly are not sure where he went, chances are that you've been dead for several seconds and haven't fallen apart yet because Gravity Is a Harsh Mistress.
 * Hiei from Yu Yu Hakusho is rather fond of this, most notably having done it to Seiryuu the Blue Dragon in the first arc (although he went a little beyond the trope to cut him a total of sixteen times at various angles, and the guy still had time for a final line), and Kurama has been known to pull something similar from time to time. With a whip.
 * Bleach: Kubo Tite is very fond of this trope. Almost all the characters that fight will, at some stage, perform a diagonal cut, be it on their opponent or some scenery around them. Most of the characters will go on to perform diagonal cuts in later fights, too. In fact, it's practically a default cut in this manga.
 * Technically performed in the anime adaptation of Witchblade, where the main heroine performs a vertical cut on a demon. After a few seconds nothing has happened and she begins to walk away. The demon cries "Hey, I'm not finished with yo-" and is cut off by his own explosion.
 * Kenshiro from Fist of the North Star displays the ability to kill enemies without them realizing their own death, but does not cut. No, this trope applies to Rei (and all the users of Nanto Suichôken).
 * Justice from Afro Samurai sets himself up as a major Badass by pulling one of these off with a revolver, holstering it after doing some Gun Twirling for extra Cool.
 * In the third episode of Hellsing Ultimate, Alucard pulls a few of these off on a SWAT team with his fingertips.
 * Almost all monsters of the week were killed this way in Voltron.
 * Referenced/parodied in the opening titles of .hack//SIGN, where some of the game characters walk on, swing their swords, momentarily split diagonally and then return to normal.
 * Setsuna of Mahou Sensei Negima does this occasionally. She has a technique explicitly made for cleaving solid rocks in two and having them fall seconds later, though less dramatically. Because of the nature of the series (at least before volume 20), she doesn't do this much (unless a paper bird falling apart in mid-flight counts).
 * Pokémon
 * This style has been known to be used in the anime, and in the handheld battle scenes the animations for attacks such as Slash and False Swipe end up looking a lot like it.
 * Pokémon Special has
 * Farfetch'd was able to do this with a green onion.
 * The manga Samurai Deeper Kyo takes this trope to its logical extreme: just about everyone who wields a bladed weapon does one at some point.
 * Although This Is a Drill and not a sword, the way the Giga Drill Breaker from Tengen Toppa Gurren Lagann goes off -- Gurren Lagann passes through the victim, swings its right arm back while retracting the drill, followed by the victim exploding -- is stylistically identical to the archetypal Diagonal Cut Single Stroke Battle.
 * Gundam Seed Destiny
 * In episode 12, Shinn does this to the bridge of a battleship. It helps that he's in a Humongous Mecha Dual Wielding BFSs at the time.
 * Later, after Shinn receives the Destiny, he uses his new Gundam's BFS (a standard weapon on this one) to do this to a giant enemy mobile suit. The Destiny drops down through frame incredibly fast, and doesn't seem to have done anything at first, until the enemy machine's two halves slide apart, a fraction of a second before it explodes. Admittedly, this is a vertical cut rather than a diagonal one, but otherwise a classic example.
 * During the same battle, Shinn orders that the twin BFSs from his old mecha be launched for his two companions to use, so that they can also slice up the other, identical giant enemy Gundams.
 * Lowe also pulls this off in Gundam SEED Astray once he gets the Gerbera Straight. At one point, an enemy Mobile Suit comes after him with his friend Kisato strapped to its head. Lowe's attack not only does this to the mecha, but catches part of Kisato's sleeve too (despite being about as thick as she is wide).
 * G Gundam's Schwartz Bruder does this to a large tree...with a dulled and rusty sword.
 * Domon's Bakunetsu God Slash has this effect as well, but since it's used on the Mandala Gundam, it has the effect of making all the balls that make up its arms and waist pop off like a broken pearl necklace.
 * Code Geass
 * Suzaku in his upgraded Lancelot Albion does this to Bismark (a.k.a. the Knight of One).
 * Way before that, mao does it. With a chainsaw
 * In the fourth episode of Diebuster does one of these to a planet from the inside.
 * Happens all the time in Murder Princess.
 * Inuyasha:
 * Inu-Yasha kills Hiten like this. Cutting through the haft of Hiten's halberd and Hiten's head and sholder.
 * When demonstrating to Jaken what Tenseiga's power is, Sesshoumaru performs a diagonal cut on him. Subverted because Tenseiga is incapable of cutting living or physical objects, so Jaken wasn't really injured. However, when Sesshoumaru later kills spirits with it, he'll often kill them via a diagonal cut. In particular, when he slashes Magatsuhi's true body, he does this to Magatsuhi's face.
 * Kaijinbou, when possessed by Toukijin, does this to Jaken.
 * Apparently Inuyasha and Sesshoumaru's father was prone to this was well. When they're fighting Shishinki, his mask breaks off his face revealing his face is partially missing from a diagonal cut. Shishinki confirms their father did that to him.
 * Parodied in a filler episode where Shippo and Soten both score one... using kendamas!
 * In Full Metal Panic, during their final battle, Sôsuke did this do the head of Gauron's AS. With a machete the size of a car. Too bad Gauron had auxiliary sensors so he didn't have to fight blind.
 * The Parasites from Parasyte prefer this method for delivering their coup de grace, oftentimes to several people at once.
 * In the Mega Man NT Warrior manga, Mega Man Protosoul debuts by combining this with both Implausible Fencing Powers and an energy attack-based Out of the Inferno, slicing through not only Bass GS' newest and most powerful attack yet, but through the dark-energy dragon he summoned to use the attack as well.
 * In Gun X Sword,
 * Done often in Afro Samurai. It's probably best demonstrated in the movie in which Afro faces off against a band of mooks, he slashes at them with his sword rapidly then puts it back in it's sheath moments later blood starts spraying from the mooks' wounds before they fall into pieces.
 * Yaiba's Kaminarigiri (Lightning Cut) attack sometimes results into this. He also uses the non-lethal variation against machines, weapons and clothes.
 * Subverted in Naruto: when Sasuke is fighting Deidara, he cuts clean through Tobi, who falls over a second later, but to Sasuke's confusion Tobi gets back up seemingly unharmed a second later.

Comic Books
""Are you kidding? That cut was so subtle it missed the target!"
 * Happens in the fourth book of Scott Pilgrim, in which the victim is actually able to get a few words in before sliding apart.
 * Hit-Girl does this to random mooks a lot in Kick Ass.
 * In one issue of G.I. Joe, Snake-Eyes demonstrates his "subtle cut" against a practice dummy. When the dummy doesn't fall apart, the following comments pop up in the background:

"Just keep watching."

(Snake-Eyes stomps the floor, and the target's head slides off)

"True subtlety is having to remind the target it's been cut.""

Films -- Animation

 * At the end of Highlander the Search For Vengeance we have a decidedly one-sided battle, after a beat-down Colin gets one final boost of energy to jump up and slice Marcus right across the face. Cue smug looks from Marcus until his head falls off. Funny enough he's still talking after his head is separated from the body, though he's not the first person in the series to do this.
 * Final Fantasy VII Advent Children
 * Done to many, many skyscrapers in the climactic duel of and to a lot of other objects (guns, a motorbike in mid-flip) earlier in the film. It helps that Cloud's weapon is basically a sharpened industrial girder.
 * At one point during the climax,

Films -- Live-Action

 * A rare Western example of the aftermath of this is seen in Monty Pythons Meaning of Life, where a British soldier falls apart like a chopped cucumber.
 * The blind swordsman Zatoichi is the undisputed champion of this.
 * In the first Underworld this happens during the final duel between Selene and Viktor. With his head no less. And it takes forever to fall off. Also note that it's done with a big, thick claymore, which should have made this much messier than it was.
 * Star Wars: The Phantom Menace. Given that the lightsaber fights in the franchise were explicitly based on Japanese samurai movies, this is not terribly surprising. Also, given the nature of lightsabers, completely justified.
 * In Piranha 3D the piranha cause a wire to get loose from the stage and it slices through two girls, one of them dies instantly the other appears to be unscathed with the only damage being her bikini top got cut off. After feeling herself to make sure she's alright, her upper half from her shoulder down to her torso slides off her body.
 * Ichi the Killer. Admittedly the cut is vertical, not diagonal, but the effect is the same: the victim delivers one final line, and his two halves slowly separate.
 * The movie Equilibrium does a perfect diagonal cut/slide apart in live action as part of its climactic fight sequence, and the victim is even courteous enough to turn his head to the side so the audience can see his face sliding off. It looks exactly as awesome as it sounds.
 * Happens in the prologue of Ghost Ship. When the cables tear through the Maria Grazia, dismembering everyone on-board, most cuts are horizontal as the victims are standing. The captain is dancing with a little girl and bends in an odd pose to protect her and, after a few seconds of delay to look around at the carnage, the girl watches the cut form across his head.
 * Interview With the Vampire
 * In the movie adaptation, Louis slashes at a rival vampire with a scythe as the latter capers past. The foe pauses for a few puzzled beats, as it appears Louis has missed -- until a diagonal section of the rival's upper torso falls off.
 * And in Queen of the Damned, Lestat slices through another vampire's neck with a long curved knife, before kicking the body, causing the head to fall off.
 * Used to the nth degree (though not with swords) in the first Resident Evil movie. A small group of characters are trapped in a short hallway with deadly lasers that cut them apart, while characters outside try desperately to deactivate them. On the last pass, the only surviving character is facing down what turns, to his horror, into a GRID of lasers. The outside characters manage to deactivate the lasers apparently in time, until the trapped character starts oozing from a grid of a thousand cuts -- and then falls apart in a fine dice.
 * In the Hellboy film, Kroenen cuts a stone statue imprisoning Sammael this way.
 * The first trap seen in the movie Cube seems to do nothing except go "schinggg" -- until the hapless victim collapses into a pile of meat dice.
 * Done in Johnny Mnemonic with a monofilament whip.
 * While not a full diagonal cut, Ice Pirates does have the momentary delay. A brief swordfight in a Bad Guy Bar has a man beheaded, but he doesn't realize it until he tilts his head back to laugh at this weak attack, whereupon his whole head falls off.
 * Humorous example from Without a Clue: Reginald Kincaid (posing as Sherlock Holmes) tries to show off in the middle of a climactic fencing duel by slicing some candles. He seems to miss, but a while later the candles get shaken and their top halfs fall off.
 * In John Capenter's Vampires, when the head vampire Jan Valek is introduced he takes a swipe at Caitlan one of the vampire hunters with his claws and after a pause he splits in half from the head down.
 * Used to patently ridiculous effect at the end of Silent Night Deadly Night Part 2. Witness: Ricky swings a wood axe, and this is the result. Words fail.
 * Done once in Ninja Assassin in the first scene, which contains most of its Gorn. The guy getting sliced was holding a shotgun in that moment, which was sliced through, too, making this also a perfect example of absurdly sharp blade.
 * In the Directors Cut of Sin City, Miho slices  in half with a spear. This scene was not in the theatrical cut or the comic.
 * Happens with a redneck in Slither, after the Big Bad's tentacle whips at him. The cut is not diagonal but perfectly vertical. And yes, it takes a few seconds for him to realize that he's already dead.

Gamebooks
"You strike again, curving the golden blade in a great arc. It bites into the Vordak's neck, tearing through its unnatural body, and severing it diagonally from collarbone to hip."
 * Lone Wolf: This is the fate of a Vordak in Book 5, Shadow on the Sand, if you have the Sommerswerd.

Literature

 * In a rare book example, in the novel The Lone Drow by R.A. Salvatore. King Obould kills an elven warrior with precisely this trope, right down to the delay between the cut and the torso sliding away. He does it again in The Pirate King, this time with an erinyes.
 * Shagga son of Dolf brags to Tyrion that he has performed such a feat with his axes in A Clash of Kings.
 * "ACEPHALOUS, adj. In the surprising condition of the Crusader who absently pulled at his forelock some hours after a Saracen scimitar had, unconsciously to him, passed through his neck, as related by de Joinville." -- The Devils Dictionary, Ambrose Bierce.
 * The first chapter of the Zombie Apocalypse novel Empire has Death himself do this to a zombie with his Sinister Scythe. It is explicitly noted that there is at first no visible wound, only for a paper cut-like effect to appear and the zombie falling apart.
 * In Carpe Jugulum, this is done, not diagonally, but straight across the neck, using a double-headed axe. Considering the victim is a vampire, he actually doesn't die, but has to walk very, very carefully after that...
 * Similarly, in Lloyd Alexander's book The Remarkable Journey of Prince Jen, a legendary sword is so sharp that a light slash with it cuts a thick tree trunk so clean in two that it remains standing.
 * In Dan Simmons's Ilium, the older Odysseus has a vibrating sword with so much cutting power that it does this, once to a tree and once to a quasi-mechanical creature.

Live-Action TV

 * An even more unlikely Western example is in CSI: New York. The villain of the episode manages this on a man's neck. Somewhat subverted in that the man does die right away -- the head just fails to fall off immediately, greatly confusing the investigators.
 * Kamen Rider 555: Takumi's BFS finalizes a Monster of the Week with such a cut... and a second later, a nearby train car slides apart, too.
 * In Kamen Rider OOO, the OOO Bash is one of these. Not only does it slice the Yummy in half with a short delay, it cuts ALL OF REALITY as well. Thankfully, the Yummy is the only thing that doesn't return to normal afterwards.
 * In the final episode of Buffy the Vampire Slayer, one of the Bringers does this to Anya from behind.
 * In the spirit of its Jidai Geki theme, Samurai Sentai Shinkenger pulls these off whenever possible.
 * In the Japanese gameshow Ken-chan's Masquerade, best known for the "Matrix Ping-Pong" clip, a sketch depicts a samurai in a tall grass field, which rotates around him, to reveal a bamboo grove and three ninja from the shadows. He makes his slashes, then sheathes his swords -- then the ninjas, the bamboo grove, and the moon slide apart, in that order.
 * Star Trek the Next Generation: Worf lands one of these on a holodeck-generated training dummy, complete with the top half slowly sliding off before the whole mook fades away.

Myths & Religion

 * Older Than Print: In certain versions of the 12th-13th century epic Nibelungenlied after Kriemhild killed Hagen, Hildenbrand slashes her waist. Initially Kriemhild, who is still on a revenge high, laughs off the attack. Hildenbrand then drops his sword and calmly askes her to pick it up, and as she does so, she falls to pieces.

Video Games
""Oh, split personality!""
 * Both Samurai Shodown and Last Blade play this trope if the last blow is a strong slash with both characters standing.
 * Johnny in Guilty Gear specializes in these. Most of his special attacks come in the form of diagonal cuts, and his Instant Kill turns the opponent into a playing card, which he cuts diagonally, whereupon it slides apart.
 * Final Fantasy
 * Squall's first limit break in Final Fantasy VIII, "Rough Divide", does this. His last one, "Lion Heart", also ends this way.
 * Likewise, the special attack "Zantetsuken", used by the Summoned Beasts Odin and Yojimbo in the many games they appear in.
 * Cyan from Final Fantasy VI can learn a similar move as his final bushido, and it's hit rate is even higher than Raiden's.
 * At one point in Final Fantasy VIII, Seifer does this to Odin.
 * And if Odin's successor Gilgamesh misses on a Zantetsuken blow, he does this to everything except the enemy combatants.
 * In Dissidia, diagonal cuts are as common as air, though the only thing being bisected is a player's Bravery gauge.
 * Just about every time the Power Slash technique is used in the video game Okami, a diagonal or horizontal slice appears, then the sliced object splits apart slowly (Sliding down for diagonal, tipping over for horizontal).
 * A partial parody of the samurai genre, in Shadow Warrior the sword often kills using the trope in textbook form. Typically followed by an appropriate Bond One Liner.


 * In the PS2 remake of Shinobi, enemies don't suffer Critical Existence Failure even when their health runs out -- they simply stop moving until you run out of enemies to kill or take too long to get to the next one, then they all fall apart messily, accompanied by a cutscene if you've chained four or more kills together. Let's not even go into the fact that Hotsuma's demonic sword can slice a Type 90 main battle tank in half like this.
 * The moon at the start of the fourth case of Phoenix Wright Ace Attorney: Justice for All. It was cut by the Nickel Samurai.
 * In Devil May Cry, Vergil and his Dark Slayer style of swordsmanship is a god of this trope. His sword Yamato seems specially able to grant smooth and stylish cuts to whoever wields it, as shown by Dante who also knows Dark Slayer, and Nero who doesn't. What's more, enemies die only the moment Vergil clicks his blade back into place.
 * Every game in the Mega Man Zero and ZX series has this happening to mooks (and most bosses) if a saber or similar bladed weapon deals the finishing blow. Then again, said mooks and bosses are all mechanical, so no censorship is required.
 * Earlier in the series, in Mega Man X 2, the Maverick boss Wire Sponge will be cut in half and explode if X deals the final blow with the Sonic Slicer.
 * Happens to Tohno SHIKI in the Akiha path in Tsukihime. Rather disturbing in that SHIKI is immortal, and in the ensuing scene runs away as a torso.
 * Kingdom Hearts
 * In the final stage of Kingdom Hearts II, a series of skyscrapers springs out of the ground to block Sora's path, who, using a reaction command, charges through every one of them and emerges at the exit, despite the fact they only slide apart several seconds later. Also, Sora's keyblade is round. It still cuts absolutely smoothly through objects several times its own length.
 * Sephiroth opens the fight this way. If you don't press triangle you basically just die.
 * Luxord dies this way.
 * In Birth By Sleep, Terra has the unique attack "Zantetsuken", which takes a moment to wind up, but has a chance of instantly killing enemies.
 * In Super Robot Wars Z, one of Asakim's attacks is this: he cuts straight through, nothing appears to have happened until he casually taps his victim, who promptly falls in two.
 * In Chrono Cross, this is Fargo's Level 7 Tech, "Invincible". Used merely as a visual effect, though, since it just deals physical damage instead of instant-kills.
 * One of the mini-games in Wario Ware: Smooth Moves has the player perform a diagonal slash with the Wiimote. The starting position is called "The Samurai."
 * Subversion in World of Warcraft: Treants will randomly die as if from a Diagonal Cut, no matter what they were killed with. Yes, even with sticks.
 * Kirby Super Star has Dyna Blade do this to the background in the intro sequence.
 * In Wii Sports Resort, one of the minigames consists entirely of doing this as fast as you can, using the direction indicated onscreen (left to right, diagonal cut, vertical cut etc). This includes cutting hilarious items such as giant sushi, giant hard boiled eggs, a giant LED timer that stops and shows the timing when cut, and giant human-sized diamonds. You can even work in a few extra iai slashes before the next item loads, if that's what you're into.
 * In Mortal Kombat Shaolin Monks, this happens when fighting the lesser enemies with a sword. This also happens with some of the finishing moves, especially Kung Lao's.
 * In Starcraft II, Zeratul manages to get one in on Kerrigan's left wing, though she somehow nails him in the arm as well. She gets better. He doesn't.
 * The Gundam vs. Series, starting with the Gundam Seed-themed games, has enemy machines split in half at the waist as part of their death animation if you finish them off with a melee attack. This vanishes in Gundam Extreme Vs, where defeated machines breaking apart pretty much randomly and regardless of what finished them.
 * In Assassin's Creed, this is one of Altair and Ezio's finishers with a sword. Mind you, they don't cut all the way and just cut as deep as the clavicle, perhaps a bit more, before removing the sword and kicking them to the ground. They also do this with an Axe.
 * This can happen in the Dead Rising series when you fight the zombies with a sharp weapon such as a sword or chainsaw.
 * In Valis II, Magus does this to the defeated Shadow Panther Gillan.
 * This is pretty much what Metal Gear solid: Rising is about

Web Comics

 * Used fairly straight -- except that Gabe's using a cardboard tube -- in this strip of Penny Arcade.
 * Happens a lot in the Web Comic Twelve Dragons, any time any of the four Legendary Swordsmen are on screen, most notably in this scene with Caoryn.
 * Subverted in Adventurers!
 * In The Adventures of Dr. McNinja, the title character fails at this trope, rife with Lampshade Hanging.
 * Real Life Comics' Black Pants Samurai does it to a titanium door with concrete frame.
 * Parodied in this strip of The B Movie Comic.
 * Sinfest "Ninja Theatre" used this among other ninja movie tropes.
 * The Order of the Stick: Roy Greenhilt cuts down an evil warrior attacking his family in the afterlife -- with "QUARTER" as an Unsound Effect.

Web Original

 * Ninja Charlie does this to Demon Rupert in the Kate Modern episode "The Wedding Video".
 * Inverted in Super Mario Bros Z, when Axem Yellow attempts a Diagonal Cut against Mecha Sonic... only for his weapon to fall apart three seconds later, with Mecha Sonic totally unharmed.

Western Animation

 * In the second episode of Transformers Prime, Megatron fights the recently resurrected Cliffjumper who is now a mindless zombie, he charges at him while Megatron slashes him with his arm sword seconds later the zombie Cliffjumper splits in half.
 * In an episode of Frankenhole, Dr. Frankestein slashes at his childhood self with a meat cleaver. A few seconds later, his head falls off.
 * American Dad
 * Roger has stolen Steve's roosters he had saved from being slaughtered as chicks to be used for cock fighting, we see one of the matches when Steve arrives one of his roosters recognizes him and it runs towards him only for it's opponent to slash it's throat, a few seconds later the rooster's head falls off.
 * In the Halloween episode Toshi fights and kills the serial killers, the second one he slices down the middle a couple seconds later he splits in half from the head down.
 * In the Animaniacs episode "Rest in Pieces", Walter Wolf and Sid Squid had set up a trap for Slappy so that if she were to step on a platform she would get cut in half by an angel statue holding a sword. When it doesn't work, Sid steps on it and the angel's sword slices through him and the floor he's standing on. He checks himself over and seems fine, only for him to split in half.

Real Life

 * The show The Deadliest Warrior examined this trope, Myth Busters-style, using a modern production katana wielded by someone without much training, and a dead pig. The sword cut through the pig with little resistance on the first try.
 * Someone without much training was a martial artist and movie fight coordinator. Also, subverting Katanas Are Just Better, so did nearly every blade tested the same way, notably Kilij.
 * The Zanbatô, a huge-ass japanese sword, was designed to slice through a horse rider, along with his horse. They had been used for this purpose, but were mostly decorative. Some historians debate whether a BFS with a handle that flimsy could have actually existed.
 * A diagonal cut, known as the Zornhau ("Wrath Strike" or "Wrath Hew") is one of the 8 basic cuts in medieval German longsword fencing, as well as one of the 5 Master Strikes -- strikes that, when executed correctly, make contact with one's adversary and defend one's own body in one technique. The masterful element of the Zornhau is the forward diagonal sidestep, which takes the swordsman out of the path of an incoming technique while covering their body and attacking all in one instant. This is ultimately a combined dodge, parry and attack.