Musashimaru Koyo (??? ??, Musashimaru Koyo, born May 2, 1971, as Fiamalu Penitani) is a former sumo wrestler.
He made his professional debut in 1989, and reached the top makuuchi division in 1991.
After reaching ozeki rank in 1994 his progress seemed to stall, but in 1999 he became the second foreign-born wrestler in history to reach the rank of yokozuna.
He won over 700 top division bouts and took twelve top division tournament championships during his career.
Musashimaru's sheer 235 kg (518 lb) bulk combined with 1.92 m (6 ft 3 1/2 in) of height made him a formidable opponent, and he was remarkably consistent and injury-free for most of his career.
An amiable personality, his fan base was helped by a surprising facial resemblance to Japanese warrior hero Saigo Takamori.
After retiring in 2003, he became an elder of the Japan Sumo Association and founded the Musashigawa stable in 2013.