Passage: After graduating Takigawa Daini High School in 2004, Okazaki signed full professional terms with Shimizu S-Pulse the following year. In December 2005, he made his first J.League appearance as a substitute against Sanfrecce Hiroshima. On 15 April 2007, he scored his first professional goal against Kawasaki Frontale. Okazaki ended his first season as a first team player with three goals from 13 matches.

Question: When did he graduate high school?
2004