Ko-Ou Ken

Ko-Ou Ken (lit. Tiger Spark/Gleam Fist) is one of the signature moves of the Kyokugenryu Style, making its initial appearance in the Art of Fighting series and being a fixture of every Kyokugenryu practitioner ever since.

Description
The user swings their arm out via a punching-palming motion, and either throws out a short-distanced surge of qi/ki/chi akin to a reinforced palm-strike, or a fully-traveling chi projectile, all depending on the user and the game.

The short-ranged surge mainly occurred in the original Art of Fighting games when the user (namely Ryo Sakazaki in such games) has an insufficient energy amount to cause the projectile to leave their hands, though in The King of Fighters series as of KOF '96, the short-ranged version becomes the main version as a viable move which instead often converts the Ko'ou Ken to be something akin to an energy-infused palm thrust. Though at a cost, anytime Ryo has the short-ranged version in his moveset, he is unable to use his original midair projectile version. The same chi-infused-close-ranged-blow-conversion dynamic has also occurred with the Rai'ou Ken in some of Yuri's movesets as well.

Masters of this technique as shown with Takuma Sakazaki of course, are able to even fire the Ko'ou Ken as an invisible puff of chi that can still strike distant targets with potency.

Strategy
Not exactly a zoning tool, but still solid enough for the neutral, this is your go-to poke when at range at times.

For Ryo's version, in KOF XV in particular, not only is the EX version still advantageous on block as it was in XIV, but it's also now a full-screen projectile that knocks down on hit, adding a layer of pressure to Ryo's gameplan. Though in older games with the short-ranged version, it's known for being a solid knockdown tool to end his combos in. In most cases, however, the move through its short-ranged variation is still very handy as a poke to use in the neutral and can even beat out certain traveling projectiles if timed right, given it also has a fairly big hitbox (even reaching a bit vertically).

In Yuri's case, she can hold either punch button (or both for the version) to throw out a rather quick and damaging full-screen projectile in the form of a meterless Haoh Shoukou Ken since KOF '99 (tied with Ventose as the most damaging, in fact). Though she's liable to be hit as she's charging up the move, making both positioning and timing crucial to make the best of it.

Ryo when he is Mr. Karate in games such as Fatal Fury: Wild Ambition, is also able to charge up his own Ko-Ou Ken for more damage.

Trivia

 * As one might guess, this is to the Kyokugenryu practitioners what the Hadoken is to the Ansatsuken users of the Street Fighter series.