When and how was the Japanese Constitution made?

As suggested by the general headquarters of the allied forces occupying Japan after World War II, the Japanese government completed a draft of the revision of the Meiji Constitution in January 1946.
In this draft, with no major changes from the original constitution, sovereignty rested with the emperor, although the people's rights were extended significantly.
General MacArthur rejected this draft and presented the socalled "MacArthur draft" on February 13 for the Japanese government's consideration.
The government drew up a new constitution based on the MacArthur draft on March 6、and it came into force on Mav 3, 1947.
Some　conservatives　in　Japan　have　criticized　this new constitution because it was something given to the people, rather than something they acquired by themselves.