How many explosions occurred at Fukoshima?

The Fukushima Daiichi nuclear disaster, which began in March 2011 following a massive earthquake and tsunami, involved a series of explosions at the plant. Specifically, there were four significant hydrogen explosions at reactors 1, 2, and 3, occurring between March 12 and March 15, 2011. These explosions resulted from the buildup of hydrogen gas due to overheating and the loss of cooling water in the reactors.