[3] Muramatsu represented Japan with Morihiro Hashimoto in the 2012 PDC World Cup of Darts and together they were beaten 2–5 by Sweden in the first round.
[9] Muramatsu lost to Taylor 4–1, but Katsumi defeated Lewis meaning that a doubles match was required to settle the tie.
[12] In the second round they both lost their singles matches against the Northern Irish partnering of Brendan Dolan and Michael Mansell to exit the tournament.
[13] A week later he won the French Soft Tip Darts Live event by beating Shaun Narain in the final.
[17] After whitewashing China 5–0, Muramatsu and Hashimoto were knocked out of the World Cup in the second round for the second year in a row this time to the top seeds England.