I want to know the answer to the following question:
What was restricted?
All the background I'm provided with is that "The number of characters in common use was restricted, and formal lists of characters to be learned during each grade of school were established, first the 1850-character tōyō kanji 当用漢字 list in 1945, the 1945-character jōyō kanji 常用漢字 list in 1981, and a 2136-character reformed version of the jōyō kanji in 2010.". Is that enough to answer the question?
Answer: yes