Japanese “Passing Grade” Button
Means “agreement” in Japanese. More literally, it means to unite, or join together.
CJK Ideographs are characters used in Chinese, Japanese and Korean languages. Their writing systems all completely or partly use Chinese characters.
Japanese “Passing Grade” Button was approved as part of Unicode 6.0 in 2010 under the name "Squared CJK Unified Ideograph-5408" and added to Emoji 1.0 in 2015.