You may see headlines today proclaiming Shohei Ohtani the new #1 Japanese HR king

He surpassed Hideki Matsui for the most MLB homers by a Japanese-born player with 176.

Of course Sadaharu Oh (who's still alive at age 83, BTW) hit 868 dingers in the Japanese Central League, mostly in the '60s and '70s. There have been numerous debates about how many MLB home runs Oh would have hit had he played in North America. It's all conjecture, of course, but this fellow took the time to study the issue in-depth.

Based on his projections, Oh would have been racked up an estimated 527 HRs in "the Bigs."

https://baseballguru.com/jalbright/analysisjalbright08.html