Seppuku wives of samurai who have performed seppuku or brought dishonor. Some women belonging to samurai families committed suicide by cutting the arteries of the neck with one stroke, using a knife such as a "tantō" or "kaiken". The main purpose was to achieve a quick and certain death in order to avoid capture. Before committing suicide, a woman would often tie her knees together so her body would be found in a dignified pose, despite the convulsions of death. Invading armies would often enter homes to find the lady of the house seated alone, facing away from the door. On
Samurai Warriors 4 , a social spin-off game released on April 22, 2014 for the mobile phones also to commemorate the series' 10th anniversary. Koei Tecmo also collaborated with the Japanese Racing Association (JRA) to release on May 25, 2014 for the PC. "Derby Musou" reuses assets from "Samurai Warriors 4" to create a horse racing game, like that of the "Winning Post" series, with famous Japanese racehorses. Eight characters from "Samurai Warriors 4" make up the playable cast, plus Matthew C. Perry (known in-game as just Perry). The game received a revision, titled , which was released in Japan on February 11,