The play Kokusenya kassen ("Battles of Kokusenya"：国性爺合戦), written by Chikamatsu Monzaemon (1653-1724), has long been considered a bunraku masterpiece. First staged in 1715 at the Takemoto no Shibai, Osaka, it remains unsurpassed as the most successful play in the history of the puppet theater. Kabuki also produced many adaptations, starting in 1716 at the Miyako Mandayû no Shibai in Kyoto.
The hero Watônai Sankan, a fisherman by trade, was also the son of Ikkan, a former Ming minister named Tei Shiryû who had been exiled to Japan. Trained in military strategy, Watônai travels to China to aid a princess named Sendan, the younger sister of the Chinese emperor murdered by the Tartars. Watonai vows to fulfill his father's promise to restore the Ming dynasty and place Sendan on the throne. He and Ikkan travel to China, where they find Ikkan’s daughter and Watônai's half-sister, Kinshôjô, married to a general named Kanki, of Ming ancestry but allied with the Tartars. Kinshôjô, loyal to her father and Watônai, agrees to ask Kanki to join Watônai, but she has them wait outside the Lion Castle for a sign of her husband's intentions: a powder —
white for "yes" and red for "no" — to be tossed into cascading water flowing down to the castle moat. Kanki is sympathetic to her request but cannot take advice from a woman on military matters, as it would bring shame upon himself and his descendents. He is also bound by a promise he has made to the Tartars to kill Watônai. Always the warrior, Kanki considers murdering his wife to quell any rumors of his being a coward, but is dissuaded by Kinshôjô's stepmother (Watônai's Japanese mother, who was allowed to enter the castle to plead their cause).
Kunikazu has depicted the celebrated scene called beni nagashi shishigajô ("the red signal inside the castle") when Kinshôjô stabs herself and, in place of the red powder, lets her blood flow into the conduit. Her death will free Kanki to fight the Tartars. Upon seeing the "red signal," Watônai bursts into the Lion Castle to confront Kanki, whereupon the two become allies and Watônai is given the name Kokusenya, Lord of Enpei.
This is a rare format for a triptych, although Kunikazu used it a few times, with similar cropping of the architectural forms. A few other artists, including the Osaka master Hokushû, also experimented with similar challenging asymmetry for an ôban triptych.
References: IKBYS-IV, no. 587;
KBP-7, p. 67; IKB-I, no. 1-591; NKE, p. 347