Tanjiro's Journal, Part 2

A boy hidden behind a fox mask invites Tanjiro to spar. Tanjiro hesitates because the stranger carries only a wooden blade, but the boy easily overpowers him and points out that Tanjiro has memorized the idea of Total Concentration Breathing without truly grasping or applying it. After dodging Tanjiro's strongest swing, the masked boy lands a blow that knocks him out, then leaves the rest of the lessons to a girl who has just entered the woods.

When Tanjiro comes to, the girl introduces herself as Makomo and names the masked boy Sabito. She begins correcting his posture, his bad habits, and his breathing. Both children, she explains, are among the many orphans Sakonji Urokodaki took in. She presses on him the meaning of Total Concentration Breathing: speeding the blood, raising body heat, and filling the lungs to grant a human enough power to rival a demon.

Sabito defeats Tanjiro in their first exchange and exposes the gap between knowing a technique and using it. Makomo then becomes Tanjiro's coach, refining his swordsmanship over the following weeks.

Six months after meeting Sakonji's students, Tanjiro faces Sabito in a final duel, this time against a real blade. He strikes first and cuts cleanly through the fox mask, which falls away to reveal a peaceful, relieved expression. Sabito and Makomo then fade from sight, and Tanjiro realizes the strike that he thought parted the mask has actually cleaved the boulder in two.

The chapter belongs to the Final Selection Arc and appears in the anime as Episode 3. It centers on the spiritual lessons of Makomo and Sabito, framing Total Concentration Breathing as the foundation of every later fight. The closing reveal, that the split mask was really the split boulder, marks the turning point of Tanjiro's preparatory training.