She gave no reply. After a while she spoke further. "There is one thing that comes to mind ..."
"You mean to explain Sensei's temperament?"
"Yes. And if it were to be the cause, then I wouldn't have to worry it might be me. That alone would be a great relief."
"What is it you're thinking?"
She gazed at her hands, which were resting on her thighs, seemingly reluctant to continue. "Here it is then. Give me your opinion."
"I'll do my best."
"I can't tell you everything. Sensei would be terribly upset if I did. I'll tell you just what I can."
I swallowed tensely.
"In his student days at the university, Sensei had one very close friend. Shortly before graduation, that friend died. He died unexpectedly." She leaned close to my ear and added in a whisper, "He died an unnatural death."
When she told me this, I couldn't help but ask how he'd died.
"That's all I'm at liberty to say. But it was after his death that Sensei began to change. I don't know what led to his death, and I suspect that Sensei may not know either. However, it's not inconceivable that his death is tied to Sensei's change."
"Is the grave in Zōshigaya that of this friend?"
"I've promised never to speak of that, so I won't. Could the death of one close friend affect a person so? That's what I need to know. I'd like your opinion on this."
It seemed, in my mind, not likely.