永楽通宝(ei raku tsuu hou) coaster

This mark was used as the flag emblem of Oda Nobunaga. It is also a copper coin that was first minted in the 9th year of the Yongle era (1411) of the Yongle Emperor, the third emperor of China's Ming Dynasty.

In Japan, during the Muromachi period, these coins were imported in large quantities through Japan-China trade and activities of the wokou (Japanese pirates). They circulated until the early Edo period and were referred to as "Yongle coins" or "Ei-sen."