Akai Katana is a horizontal bullet hell shoot 'em up developed by Cave and released in 2010. An enhanced Xbox 360 port, Akai Katana Shin, was released in 2011. An ultimate version called Crimson Katana Exa Label featuring a new Exa Label mode along with all of the modes from the original arcade release and the Xbox 360 port was released on February 17, 2022 on exA-Arcadia.
The game allows the player to choose between three different ships, each with two characters (one pilot and one gunner/ninja) and an option. Once a meter fills it becomes possible to enter ninja mode, in which the ship transforms into the ninja character and its two shot types (spread and focused) are replaced by an offensive and a defensive mode. In offensive mode, the character fires an extra powerful shot. In defensive mode, all bullets get reflected when they come close enough, and enter a state in which they continuously home in on the player character until Ninja Mode is deactivated or the enemies that fired them destroyed. If said enemies are destroyed before Ninja Mode is deactivated, the bullets turn into gold that circles the player until the end of Ninja Mode, when the ship absorbs them and the player's score is boosted.
A special edition PCB was released three months after the original's release. It brought a number of tweaks and changes including the elimination of the option for coin-operated play, the removal of circling gold in order to reduce slowdown, the addition of a stage select feature, and a new, extra hard mod called Red Mode.