Japanese samurai were particularly drawn to Zen Buddhism due to its emphasis on discipline, self-control, and the cultivation of a calm mind. Zen practices such as meditation (zazen) promoted mental clarity and focus, which were essential qualities for a warrior. The principles of Zen also aligned well with the samurai ethos, which valued loyalty, honor, and a strong sense of duty.
While Pure Land Buddhism and Shingon Buddhism offered different spiritual perspectives—Pure Land focusing on devotion and faith in Amida Buddha, and Shingon incorporating esoteric practices—the samurai found Zen's practical approach to achieving enlightenment and its focus on personal experience to be highly relevant to their lives as warriors. Confucianism, with its emphasis on moral conduct and social harmony, also influenced samurai ethics but was less directly associated with their martial practices.
In summary, among these philosophies, Zen Buddhism was the primary path that resonated with the samurai's ideals of discipline and self-control.