That doesn't sound right. It should be when you exercise the options or when you sell the stocks:

> Basic taxation of stock options depends on whether they are qualified stocks or unqualified stocks. The qualified stock option is not subject to Japanese income tax until it is sold, on the other hand the unqualified stock option is subject to Japanese income tax when it is exercised and sold.

http://tk-tax-accounting.com/en/english-taxation-of-stock-op...

We spent a bunch of money and time getting this right for cross border options. YMMV.

Might be because foreign options cannot be qualified. IANAL.