Sierra1

5th Nov 2017

Question: Mariko said to Yukio that she could not tell her something now, on the night Yashida faked his death - what could she not tell her?

Answer: Yes, She didn't want anyone else to hear about it until the will was announced 3 days after Yoshida's death.

Answer: That Yashida was going to leave the company and his fortune to her in his will.

Why couldn't Mariko tell Yukio that? In case the Yakuza were eavesdropping?

I think because she wanted her father (Shingen, Yashida's assumed heir) to know first, and to tell anyone else before him would dishonor him.