Some of the simplified characters arose centuries ago and were in everyday use in both China and Japan, but they were considered inelegant, even uncouth.
After World War II, simplified character forms were made official in both these countries.
An example is the character for "electric", which is still the traditional form of "電" in Japan, but has been simplified to 电 in mainland China (pronounced "diàn" in Chinese, and "den" in Japanese).
Prior to the promulgation of the tōyō kanji list in 1946, kyūjitai were known as seiji (正字, 'proper/correct characters') or seijitai (正字體).
Even after kyūjitai were officially marked for discontinuation with the promulgation of the tōyō kanji list, they were used in print frequently into the 1950s due to logistical delays in changing over typesetting equipment.
The modern form (shinjitai), which appears in the Jōyō Kanji List, is given in parentheses.