I sometimes play the game of going back in history by a set number of years. I did that in 1995, for example, when there was some excitement about the 50th anniversary of the U.S. defeat of Japan in Word War II.

By going back half a century from 1945, you reach 1895, when Japan defeated China in a war over Korea.

Another 50 years back, you get to 1845, when Japan's two-century old isolationist policy — partial because it accepted trade with Holland, China, Korea, and Ryukyu (Okinawa) — was becoming untenable.