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What if Japan colonized key points on the coast of Taiwan in the early 1600s, coincident with their subjugation of the Ryukyus?

Reducing the interior can take a long time, but the Japanese presence preempts Dutch, Spanish, Míng loyalist and Qing regimes on the island, by taking the main harbors of the coast.

The island supports the nanban-era red seal ship trading system while it lasts. Over time the Japanese and Ryukyuan population comes to predominate, although many Chinese individuals and families may immigrate and somewhat assimilate.

Then Japan goes into Sakoku. Perhaps the Dutch trading port is in Taiwan instead of Nagasaki.

So Taiwan becomes Japanese rather than Chinese.

Then slap a butterfly net over things until the Perry Expedition and Meiji restoration begins. What are the consequences of Taiwan being another home island of Japan in the 19th and 20th century?
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