shinjitai; new character form; simplified kanji form
Refers to the simplified kanji forms officially adopted in Japan after 1946, as opposed to 旧字体 (kyūjitai).
See also: 旧字体
"国" is the shinjitai form of "國".
I look up the differences between shinjitai and kyūjitai.
extended shinjitai; unofficial simplified kanji forms
Compound of 新 (new) + 字体 (character form). The term became common after the 1946 Japanese script reform.