Shusaku (born as Kuwahara Torajiro, June 6, 1829 - September 3, 1862) is considered by many to be the greatest player of the golden age of Go in the mid-19th century. He was nicknamed "Invincible Shusaku" because of his perfect score of 19 successive wins in the annual castle games.
Shusaku is one of three Go players of the game of Go to ever be awarded the title of "Go Saint" (Kisei). The other two are Dosaku (1677-1702) and Jowa.
He was born in a village near the town of Onomichi, Japan the son of merchant Kuwahara Wazo. Lord Asano, the daimyo of the region, after playing a game with him, became his patron, and allowed him to get lessons from Lord Asano's own personal trainer, the priest Hoshin, a player of professional level.
In 1837, only 8 years old, but already almost of professional level, he left home to join the Honinbo school, the most important institute in the game of Go in Japan at the time. On January 3, 1840, he got his shodan (first dan professional) diploma.
In 1840 Shusaku left Edo to visit his home for a period of over a year. In the next years, he made steady progress, reaching 4 dan in 1844, when he again visited home for a prolonged period. In April-May 1846, returning to Edo, he played against Gennan Inseki, arguably the strongest player of that time. Shusaku played with a handicap of two stones, but Gennan found that he was too strong, the game was left unfinished, and a new game was started with Shusaku just playing black. Gennan played a new joseki (opening variation in a corner), in which Shusaku made a mistake. All people watching the game thought Gennan was winning, except for one, a doctor. He noticed that Gennan's ears became red after a specific move of Shusaku's in the middle game; a sign that Gennan was surprised. This game is one of the most famous in the game of Go, and the "ear-reddening move" is probably the most famous single move.
Returning in Edo, Shusaku not only got promoted to 5 dan, but he was also made the official heir of Shuwa, who was to become the head of the Honinbo house. Shusaku declined at first, citing his obligations towards Lord Asano as the reason. After that issue was settled, Shusaku accepted.
As the official heir to the head of the Honinbo house, Shusaku had an eminent position. His grade also increased, he finally reached 7 dan, although it is not known exactly known when, some think in 1849, others in 1853. After forcing his main rival Ota Yuza to take a handicap, he was generally accepted the strongest player with the exception of Shuwa.
In 1862, a cholera epidemic swept through Japan. Shusaku tended the patients within the Honinbo house, and fell ill himself, dying of it on September 3.
Shusaku's name is connected to the Shusaku fuseki, a certain method of opening the game on black, which was developed (but not invented) to perfection by him, and was the most popular opening during the early and middle 20th century.