U.S. President Joe Biden said on Monday he would be willing to use force to defend Taiwan, in a series of critical comments about China he made in Tokyo that an aide said represented no change in U.S. policy on the self-ruled island. Biden’s comment, made during his first visit to Japan since taking office, and as Japanese Prime Minister Fumio Kishida looked on, appeared to be a departure from existing U.S. policy of so-called strategic ambiguity on Taiwan. China considers the democratic island its territory, part of “one China”, and says it is the most sensitive and important issue...