Japan's identity began to emerge during the

period.

I believe that you mean it's cultural identity-in which the Tokugawa Shogunate or the Edo Period would work.

Explanation:

This was the period in history where it was last isolated, and after it toppled the Meiji Restoration happened and Japan began to open up to outsiders. It was a period of peace of 250 years and where a new merchant class was formed, the population increased rapidly and urbanization occurred, but the isolation increased to block off western influences like Christianity.