Talking Through Technique

""This is not a blockade. This is language. A new vocabulary, the likes of which the world has never seen! This is President Kennedy communicating with Secretary Khrushchev!""

- Robert Macnamara, Thirteen Days

Two characters need to communicate, but can't. They might know they're Being Watched and don't want to give away vital information, or can't transmit or receive messages by normal means. However, both share a common talent at some game, combat style, art form or other skill. They're experienced enough thanks to practice and knowledge of it that they can analyze the moves to tell what their friend on the other end is thinking. So what they end up doing is Talking Through Technique, passing information not through words but through actions, and interpreting them.

Observers and spies will be very, very confused by this. They'll assume their Cryptic Conversation is deeply layered Spy Speak, when both are actually talking with chess pieces, fists, or interpretive dance. On that note, this kind of communication can be highly interpretive, analytical, or both! Often, the best way to make these communiqués secure is to require a final bit interpretive of inductive reasoning to avoid decoding by third parties. This communication likely isn't perfect, but it's a lot more secure, and if paired with a normal conversation can add enough subtext that it becomes Spy Speak.

A few possible variations include:
 * Using a game of chess, or any other strategy game, either through the moves themselves or using their names.
 * Using different combat techniques and stances.
 * Playing musical pieces in sequence (or through notes) that can decode a message.

Naturally, if the signal is misinterpreted due to a completely irrelevant misunderstanding of chess rules or somesuch, this may result in the whole "conversation" being misunderstood. An especially devious communicator may anticipate this and deliberately send out a clue indicating that he is not at liberty to communicate freely.

Contrast I Do Not Speak Nonverbal. Compare Hand Signals, where signaling is done by use of hand gestures, and Double Meaning.

Anime and Manga

 * Subverted in the Cowboy Bebop episode "Bohemian Rhapsody". The crew of the Bebop thought that the chess pieces they found on apprehended thieves might hold some secret message, but they were merely a signal from the mastermind to his former employers that it was he who was pulling the jobs. He had a reputation as a chess lover.
 * Invoked in Naruto when Sasuke fights the title character. Sasuke says that two powerful ninja are able to understand each other's thoughts just by fighting.
 * Ichigo in Bleach is able to understand the feelings of his opponents by feeling them through their sword clashes. It was how he knew.

Comic Books

 * Batman communicated with Cassandra Cain/Batgirl via combat, which makes sense since her father had overwriten the language center in her brain to better her combat training.
 * According to the "Hawaii 2.0" arc in the Wild CATS comics, the Coda have a martial art that doubles as a language. Zealot and Nemesis use it to talk past an immortal madman with microscopic vision and superhearing.
 * Played for Laughs in Nodwick when it's revealed Piffany can receive and interpret entire speeches from Nodwick, based entirely on various expressions of despair in his face and angling of eyebrows.

Fan Works

 * Played with in a game of shogi between Shikamaru and his father Shikaku in Escape from the Hokage's Hat. Shikamaru plays according to no conventional defensive prescription, but instead plays each of his pieces as one of his age group against his father's remainder of the Konoha ninja. After the game, Shikaku notices that while his position is technically weak, he's put all of his pieces in position to assassinate most of Shikaku's--which is, correctly, taken as a declaration of allegiance for Naruto and the second generation against the older shinobi, who mostly hate him.

Films -- Live-Action

 * In Red Cliff the two strategists talked through playing music together and in fact the most vital question of their whole meeting was asked and answered this way.
 * "We're leaving? We didn't get the answer." "It was in his music."
 * The twist at the end of Alfred Hitchcock's The Lady Vanishes is that the lady in question is a spy. Her secret message is encoded as a song melody. We are never told what it means.
 * In The Hunt for Red October, Alec Baldwin's US Navy character communicates with Sean Connery's character, the captain of a USSR submarine, by using morse code in flashing lights attached to their periscope. Since the USSR captain couldn't respond with morse code (the code would be recognized audibly by the crew of his ship if he tapped it out), they resorted to yes/no questions he could answer by sending a sonic range verification 'ping' to the US sub.
 * Bat 21 staring Gene Hackman, based on a real life rescue in which a downed pilot's knowledge of golf was used to give him directions when he was Trapped Behind Enemy Lines—the directions matched the layout of various golf courses he had played.

Literature

 * The Drasnian secret language, of the Belgariad, by David Eddings. All Drasnians involved in the intelligence community (which apparently means all of them) are taught a language. On more than one occasion, two such speakers converse verbally about something unimportant while having a completely separate discussion with their hands. The language is specific enough that a speaker can gesture with a recognizably outlandish "accent".
 * Subverted in Tad Williams Otherland. Mr. Sellars, who is kept prisoner in a government Gilded Cage, has a play by letter chess partner. His captors spent weeks trying to crack the code in the letters and moves, because he seriously is that intelligent. However their messages were actually contained in a packet of nanomachines in the final period.
 * The technique-plus-normal-speech version shows up in the Star Wars Expanded Universe short story "Fool's Bargain". A squad of Imperial troops, trying to help overthrow a corrupt warlord with the help of the local population, work out a Trojan Prisoner ploy with a militia group. To communicate with one another in front of the enemy, they alternate truthful and lying statements, using a code to tell the others which is which.
 * Star Wars Expanded Universe has many examples of this. Twi'leks use a subtle form of communication with their head-tails in addition to Galactic Basic. The Lorridians spent centuries under alien occupation, and being forbidden to speak openly, resorted to a series of body language tics that are a language unto itself. The Echani view combat as a form of communication, and have elaborate forms of ritual combat for everything, including courtship rituals.
 * Spider Robinson's short story "Tin Ear" involves two men in remote solar outposts who, upon being captured by an alien and learning that their communication is monitored, continue their exchange of song snippets, but now with embedded clues in the titles of the pieces.
 * In the short story Down on the Farm of Charles Stross' The Laundry Series, the titular "funny farm" is an asylum for genius-level civil servants working in the Laundry. Since their service deals with Eldritch Abominations on a regular basis, an insane necromantic scientist is a bit of a security risk; hence the building is sealed off tight from the outside world and insulated in every form imaginable. Communications with the outside world tend to be on the imaginative side.
 * In The Sorceror a spellcaster who could not use magic at this time suspected the presence of an invisible enemy. He moved his fingers through the somatic components of a spell he wanted until a wizard looking at him understood and cast it.
 * In the Exordium series by Sherwood Smith and Dave Trowbridge, a group of prisoners use subtle hand gestures to indicate which of the many words they are saying are actually significant, thus allowing them to carry on two parallel conversations. Shortly afterwards, one of the prisoners gets to communicate with someone on the outside, with the resulting conversation using both this technique and one built around understanding obscure allusions. Actually, a lot of the conversations through throughout the series involve obscure allusions that only some of the listeners are expected to get.
 * Robert A. Heinlein's short story Gulf has two supergenius spies locked in a monitored cell communicate through a game of cards.

Live-Action TV
"The Doctor: There is just one thing you've forgotten. Emma: What? The Doctor: Daleks don't have noses. Emma: Scraping the barrel a bit there, aren't you? The Doctor: Think, my dear! Back on Tersurus The Master and I both bribed the castle architect. Not only do I speak perfect Tersuran, so does he. Emma: You mean...? The Doctor: Yes! I can communicate with the Master by carefully controlled breaking of wind. Emma: Could I be tied to a different chair?"
 * There was an NCIS episode where people were communicating in code through a MMORPG or something; they managed to crack part of it, but didn't crack it all perfectly and accidentally ordered a hit on someone while trying to arrange a meeting.
 * The Red Nose Day charity spoof Doctor Who and the Curse of Fatal Death had a particularly humorous example of Talking Through Technique, coupled with Bizarre Alien Biology and Toilet Humor


 * This is a parody of a scene in Spearhead from Space, where the Doctor can communicate in Delphon by wiggling his eyebrows.
 * The Covert Affairs episode Horse to Water used the standard Chess version: an ex-CIA operative imprisoned for a decade using a slow chess game to get secrets outside to be sold. Played with slightly in that the daughter he was playing with just thought she was playing chess with her wrongly-accused father: he kept the game in his head, but she kept its state on a board in her house, which his other daughter was reading for its secrets.

Videogames

 * Touhou Project official side-story Silent Sinner In Blue dissapointed many fans as a Gambit Pileup and Shaggy Dog Story thanks to an absolutely excessive amount of this going on between Yukari, Yuyuko, Patchouli and Remilia (in a rare bout of Crouching Moron, Hidden Badass), Eirin, and possibly a couple other characters playing a crazy game of Xanatos Speed Chess that went completely over the heads of the main characters and most of the audience that just gave up on trying to read all the subtext.

Western Animation

 * In Avatar: The Last Airbender, games of pai sho are used to identify fellow members of the Order of the White Lotus. It seems to also include a number of sign-countersign phrases associated.
 * In an episode of Scooby Doo a kidnapped composer leaves behind a peice of sheet music that doesn't sound right. When converted into letter notation, it spells out the kidnapper's name.

Real Life

 * In regards to the page quote, the real life Cuban Missile Crisis was an example from the points of view of President Kennedy and Secretary Khrushchev, as the crisis descended upon them with little warning and the two could not communicate directly, having to rely on their government's words and actions (which didn't always tell the other side what they wanted to say). It was this Crisis that spurred the establishment of the Washington-Moscow hotline, which allowed both heads of state to get on the phone at a moment's notice and talk to each other more directly in order to avoid another one.