Portland is typically 17 hours behind Tokyo. When it's 1:00 AM in Tokyo, it's 8:00 AM the previous day in Portland. Japan does not observe daylight saving time, but Portland does.
During US daylight saving time (March to November), the difference is 16 hours. During US standard time (November to March), the difference increases to 17 hours.
Optimal meeting window: 3:00 AM - 5:00 AM Portland time (7:00 PM - 9:00 PM Tokyo, or 8:00 PM - 10:00 PM in winter). Very early morning Portland catches evening Tokyo.
Portland has a sister city relationship with Sapporo, Japan, and Nike (headquartered nearby) has extensive Japanese operations and partnerships.