CJK Compatibility
CJK Compatibility is a Unicode block containing square symbols encoded for compatibility with East Asian character sets. In Unicode 1.0, it was divided into two blocks, named CJK Squared Words and CJK Squared Abbreviations.
The square forms can have different presentations when they are used in horizontal or vertical text.
For example, the characters and should look different in horizontal and in vertical right-to-left:
Characters U+337B through U+337E are the Japanese era calendar scheme symbols Heisei, Shōwa, Taishō and Meiji . The Reiwa era symbol is in Enclosed CJK Letters and Months.