Gideon Ploy

""When I blow the trumpet, I and all who are with me, then blow the trumpets also on every side of all the camp and shout, 'For the LORD and for Gideon.'""

- Judges 7:18

Strength in numbers can be good. Having a vast force at your disposal can be very intimidating to the opposition. It can make you seem like you have great control over the situation and plenty of backup if things get ugly.

But what do you do when you don't have a whole bunch of mooks on your employee roster? If it's just you and some friends or even a solo act?

Well that is where the Gideon Ploy comes in! Through clever acting, disguises, misdirection, decoys, and other such feats, you make the opposition think you have more in your ranks than you actually do.

Compare To Win Without Fighting.

Anime and Manga

 * Tried in Girls und Panzer: This Is the Real Anzio Battle! Unfortunately for Anzio, the tournament set an upper limit to the number of units allowed by each side in the battle, Anzio put out too many decoys, and our protagonists know how to count.

Literature

 * Silver Shadows (a Forgotten Realms novel by Elaine Cunningham) had a moment when Arilyn used shrieker essence to amplify footfalls of centaurs, so that but a handful running at each flank would sound like a big cavalry charge and demoralize a bunch of mercenaries her side fought and make them waste time, while most attackers advanced from a different direction and on foot.

Live-Action TV

 * The main characters of Burn Notice sometimes employ this tactic, especially when they need to fool someone into thinking that Team Westen is actually a large and far-reaching secret agency.

Mythology and Religion

 * Our Trope Namer, of course comes from the Book of Judges in The Bible, where Gideon leads an army of only 300 Israelite warriors against the Midianites, who are described as having wall-to-wall camels. Gideon's night-time ambush and making his army seem far bigger than it was, aided by some holy PSYOP support from God, resulted in the Midianites slaughtering each other.

Real Life

 * The battalions of inflatable decoys in World War II served this purpose.
 * Georgy Zhukov in 1946 was about to be punished for his misdeeds (which included looting by trainloads, as well as aiding and abetting people close to him looting in comparable amounts, and of course this rolled down the ranks), as well as failures. But the other commanders defended him (if chided a little), as a matter of self-preservation: they remembered how The Purges of 1937-39 have started. Agreeing that Zhukov deserved it is one thing, but he won't fall alone, and who can tell how far things will go this time? This gave those not involved an impression that Zhukov had great support in army and allowed him to contend for power against Nikita Khrushchev. For a while.
 * The bluff was called in 1957, and the very same commanders took turns reciting all Zhukov's failures and denouncing him before Central Committee of the party, as an egotistic brute who got too high by being repeatedly Kicked Upstairs, wasted troops for nothing and ordered way too many death sentences. Nobody have defended him. Which, of course, also was self-preservation: it's one thing to make an excessively sadistic commander someone else's problem, and entirely another to let him have more power over oneself. Also, this zigzag of attitudes had a rather ironic epilogue in his near-beatification by propaganda after Khrushchev was overthrown too.
 * "Quaker" guns (a slur on the Society of Friends who are renowned as a pacifist sect) were often used in the black-powder age. A log was disguised so that it would look like a cannon in a spyglass thus multiplying the presumed artillery power.
 * A trick that is Older Than Dirt is to build campfires in the sight of the enemy, leave a small party to tend them and move the rest of the army to where the strike is desired (or if it be the case, extract an army from an engagement). Possible refinements include having troops nearby party loudly.
 * During the Second Punic War Hannibal was stalemated in Italy. His brother Hasdrubal was just coming to reinforce him and sent a messenger to that effect which was intercepted telling where Hasdrubal was. The Roman General, Gaius Claudius Nero (not the same as the Emperor of that name) watching Hannibal marched a detachment from his camp of several thousand out at night to join the army waiting for Hasdrubal and destroy him in the Battle of the Metaurus and returned in time before Hannibal could realize the reduced strength of the Romans opposing him. James Dunnigan, in Victory and Deceit gives that as an example of the "campfire trick", for according to the Strategematicon Gaius had left behind orders to maintain regular patrols of the same amount (which means said patrols would have to work proportionately harder), and light the same number of campfires working extra hard to make sure they could not be noticed and in general maintain a camp appropriate to the difference between the troops present and the one's who had moved out.
 * When Gaius arrived at his destination he forbade his men to make camp thus making them shiver for the purpose of making the enemy think the Romans had fewer troops facing Hasdrubal, which is kind of an inversion.
 * When Erwin Rommel first landed in North Africa he held a review in which he paraded his men in a circular march in the hope that enemy agents would notice the length of the march and not the fact that the same units reappeared. This is more to be congratulated as the British were good in the deception department themselves.
 * Operation Compass, the first Allied land victory or at least one of the first, is a downplayed version. The Imperial army made a series of demonstrations that if it did not involve real killing would resemble mischievous adolescents. The goal was to test the Italians, cause a little damage, steal the initiative, and generally raise a ruckus. But it was also partially to deceive them into thinking they faced a larger force than they did and that was the most important result. The Italians either retreated in panic or remained in their trenches in equal panic and in either case were outmaneuvered when the Imperial offensive started in earnest.
 * An inversion was the Double Cross System. The British managed to turn a number of key German agents. With this they were able to intercept further insertions of agents who were given An Offer You Can't Refuse. This project meant the British controlled every "enemy" agent in Britain and they refined this by creating "notational agents": cover ID's without an actual human attached to them existing only on the testimony of the "German" agents who supposedly recruited them. They took this so ridiculously far that once when a scheduled operation took place where it could not avoid being spotted by a notational agent they gave him a notational death and had a notational funeral. This is an inversion in the sense that instead of the British making the enemy think they were stronger than it actually was they made the Germans think their own team was stronger than it was.
 * Only partially a ploy but as much a natural result. In a successful blitzkrieg there will be a mobile force behind enemy lines while the attacker's infantry is keeping the breach to allow friendly supply columns through. The effect is that everyone around in the defender's camp will hear rumors of enemy troops down the line, and the sum total will put "ghost" units on different roads that are really sort of a "reflection" of the real ones, that was multiplied by rumor.
 * A rather childish one that was more a vanity project than anything else was done by Benito Mussolini and fooled no one except culpably lazy intelligence officers, and of course the press. Mussolini wanted his army bigger than it was so he not only recruited too fast (making it under-officered) but even more absurdly increased his number of divisions by taking subunits out of the order of battle of each division and creating new divisions out of them.