Ryunosuke Umemiya (梅宮 竜之介 Umemiya Ryūnosuke), usually called "Wooden Sword" Ryu (木刀の 竜 Bokutō no Ryū), is a character in the anime and manga Shaman King. In the English anime, his name is Rio.

Ryu in the beginning of Shaman King is a gang leader who is always on the lookout for the "Happy Place" (The "Sacred Hang" in the English anime; His gang is known as the "Dead Enders" in the English anime). His gang includes Ball Boy (B Boy in the English anime) and Muscle Punch (Magnet in the English anime).

Ryu comes off as being not too bright, and really thinks more about girls and his "'do" than anything else; however, he is quite deep and philosophical and turns out to be a magnificent shaman. He later gets a spirit ally, Tokagero (Tokageroh). Rio's goal in the English anime is to be Shaman King so he can get a 'First Lady' or 'Shaman Queen' to call his own. In the manga and the Japanese anime, Ryu's goal is simply to support Yoh Asakura in becoming the Shaman King.

Ryu's nickname comes from the fact he carries a wooden sword, or bokutō. In the English anime, Rio has a Hispanic accent.