Sorai was born the second son of a samurai who served as the personal physician of Tokugawa Tsunayoshi ( 徳川綱吉 ) , who would become the fifth shogun .
Sorai was born the second son of a samurai ( a warrior ) who served as the personal physician of Tokugawa Tsunayoshi ( 徳川綱吉 ) . Tsunayoshi would become the fifth shogun .