After Japan lost WW2, the island of Taiwan they had annexed in 1895 was turned over to the KMT, who moved their capital to Taiwan as a result of losing the Chinese Civil War to the CCP and ruled the island as a one-party dictatorship with martial law lasting from 1949 to 1987, during which they killed and imprisoned many dissidents. https://en.wikipedia.org/wiki/White_Terror_(Taiwan)

Taiwan has only been democratic since the 90s. Before that, the only thing distinguishing their government from that of Mainland China was their anti-Communist ideology.