San Francisco is typically 17 hours behind Tokyo. When it's 3:00 PM in Tokyo, it's 10:00 PM the previous day in San Francisco. Japan does not observe daylight saving time, while California does.
During US daylight saving time (mid-March to early November), the difference is 16 hours. During US standard time (November to March), it's 17 hours.
Optimal meeting window: 4:00 PM - 7:00 PM San Francisco time (9:00 AM - 12:00 PM Tokyo next day). This catches morning business hours in Tokyo.
Tech companies with Tokyo offices often schedule calls at 5:00 PM Pacific to catch 10:00 AM Tokyo.