One would expect that all simplified characters would simultaneously also be z-variants or semantic variants with their traditional counterparts, but many are neither. It is easier to explain the strange case that semantic variants can be simultaneously both semantic variants and specialized variants when Unicode's definition is that specialized semantic variants have the same meaning only in certain contexts. Languages use them differently. A pair whose characters are 100% drop-in replacements for each other in Japanese may not be so flexible in Chinese. Thus, any comprehensive merger of recommended code points would have to maintain some variants that differ only slightly in appearance even if the meaning is 100% the same for all contexts in one language, because in another language the two characters may not be 100% drop-in replacements.