The causes were multiple: The new Meiji-era government was steeped in Nationalist Shinto ideals. They sought to "purify" Shinto of Buddhist influence and control by strictly mandating the separation of the two religions, which had long had a more fluid and interpenetrating relationship.
The people were allowed/encouraged to release pent-up frustration over the previous system, under which they had been forced to support Buddhist temples, often at great financial cost to poor communities.
There was also a sense that Japan needed to modernize to avoid the fate of the declining Chinese Qing Dynasty. The new government saw Buddhism as backwards, intellectually stagnant, corrupt, and associated with China and India. They wanted to replace declining China with the west as the prime locus of foreign cultural and technological inspiration.
One result:
Quote source:
...a nationwide anti-Buddhist outburst referred to as Haibutsu kishaku (廃仏毀釈, lit. "abolish Buddhism and destroy Shākyamuni").
As a result, thousands of temples were closed, their land confiscated, and temple bells smelted for bronze. Bettō (別当), monks who performed Buddhist rites at shrines and jingūji (shrines part of a temple) were given the choice of either returning to lay life or to become Shintō priests...
In some areas, official antagonism escalated into a full-blown outbreak of violence against temples, statues, and priests. According to some estimates, nationwide up to 40,000 temples were destroyed. In some provinces, 80 per cent of all temples were demolished. In Chōshū, modern-day Yamaguchi Prefecture, Buddhist temples had practically ceased to exist.
https://jref.com/articles/shinbutsu-bun ... dhism.468/
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