Ninja is a Sino-Japanese compound derived from the two kanji (Japanese characters of Chinese origin) used to write shinobi-no-mono, one of the native Japanese words for people who practice ninjutsu (sometimes transliterated as ninjitsu). Ninja and shinobi-no-mono, along with shinobi, another variant, became popular in the post-World War II phonetically with the kanji, has been traced as far back as Japan's Asuka period, when Prince Shotoku is alleged to have employed one of his retainers as a ninja. This is a fighting games between two ninjas, you can choose your ninja at first, and then in the battle, use the keys A and D to attack, arrow keys to move, spacebar to launch special attack.