Japan is trying to revise its Constitution and the prime minister recently expressed his country's wish to become a permanent member of UN Security Council, then Japan shall play a more active role in the international Community.
The heaviest challenge Taiwan and Japan face is the rise of China. The increasing pressure of China goes beyond the economic competition. Beijing has developed modern military force and also naval crew to reach up to a position that excelled as super power in the Asia Pacific region. China's missiles aim at Japan, Taiwan and Korea.
Taiwan and Japan both are maritime nations and can give good results in security and economic ground. Taiwan inspires Japan to play a bigger role in the UN and on the cross strait issues. Taiwan is on its way to a sovereign nation with normal diplomatic relations with China and the rest of the international community. The ultimate objective is to work out the Taiwan Strait issue with China peacefully.

