The men's 200 metre breaststroke event at the 1956 Olympic Games took place between 30 November and 6 December.
Because an Olympic-size swimming pool is 50 metres long, this race consisted of four lengths of the pool.
Three heats were held; the swimmers with the fastest eight times advanced to the Finals.
A loophole in the rules allowed swimmers to swim below the surface of the water, which was quicker and more efficient, with Furukawa spending 75% of the race underwater.
Underwater swimming was banned in early 1957.