Shōgorō Yano, founder and head instructor of the Shudokan judo school, is a middle-aged master embodying wisdom and discipline. He serves as the primary mentor to Sanshiro Sugata, guiding him in technical judo skills and spiritual development, based on the historical judo pioneer Jigoro Kano.

Yano first demonstrates formidable skill near a river, effortlessly dispatching a group of confrontational jujitsu practitioners by throwing them into the water with calm efficiency. This display inspires Sanshiro to seek his tutelage. As an instructor, Yano emphasizes that judo transcends physical technique, integrating martial discipline with respect for life and humanity, contrasting traditional jujitsu's combative nature.

When Sanshiro exhibits uncontrolled aggression in a street brawl, Yano sharply criticizes his lack of self-discipline, comparing teaching him to "giving a knife to a madman." This leads to Sanshiro's symbolic rebirth in a lotus pond, after which Yano accepts his renewed commitment to judo's philosophical principles.

Preparing Sanshiro for a critical police-sponsored tournament against Hansuke Murai's rival jujitsu school, Yano advises pure focus, stating victory requires becoming "as pure as the moonlit flower" that inspired Sanshiro's transformation. Following Sanshiro's tournament victory and personal conflicts, Yano continues providing guidance, acknowledging his growth while noting lingering immaturity, remarking Sanshiro remains "just like a baby."

Yano's teaching extends beyond physical training, incorporating spiritual guidance through interactions with a Buddhist priest at their temple. He directs Sanshiro toward self-reflection during moral dilemmas before important matches rather than offering direct solutions. Yano consistently represents judo's integration of physical mastery and ethical development throughout Sanshiro's journey.