Koyama dojo was not what it used to be. It had way more students now, and after Zhang Heng's motivational speech, many came in early to train, forcing Zhang Heng, who was just a wall away, to develop the habit of going to bed getting up early.
When Akane found him, he had already washed up and was getting just about to go for a run.
Knowing that Okita was literally knocking on death's door, Zhang Heng had long given up hope of fighting a duel with him. Furthermore, in the current state he was in, Okita wasn't even expected to last one round. Even though Zhang Heng was stuck between levels 3 and 4 and had no way to move past that stage, the last thing he wanted was for Okita to sacrifice his life.
However, when Zhang Heng saw Okita, he knew that he would not talk the man out of the duel.
So, in the end, both ended up in Zhang Heng's little courtyard at Zhang Heng's request. Regardless of who won, he did not wish for the duel's result to be made public.
