Also check SFO/LAX-TPE and TPE-NRT (or TPE-KIX or wherever you want to be in Japan) separately on China Airlines.

For whatever reason Delta.com doesn't show China Airlines connecting options if you search LAX-NRT, but if you search segment-by-segment and find flights with availability, a phone agent can put them together for you for 80K one-way. Availability is usually very good.