Japan won't concede anything just yet. The Japanese respect only power, economic strength, and cultural proliferation. Until China's GDP is at least 5 times larger than Japan's, and the Chinese have finally abandoned their communist experiment and restored their traditional cultural prestige, Japan will not concede to China and will not sincerely view China as an equal. If China achieves all that though, then all bets are off. The Japanese could very well abandon the US and go back to their historical "Kanji cultural sphere" China-fetish again. In some sense then, a democratic and prosperous China could be the biggest threat to American dominance in East Asia.
The Japanese have a tendency to either look down or look up to other nations. Ideas of equality do not swallow well for them.