Career
She threw second stones for Ayumi Onodera at the 2006 Winter Olympics, finishing 7th, and played second for Moe Meguro at the 2010 Winter Olympics, finishing 8th. She skipped the Japan team at the 2002 World Junior Curling Championships, finishing last. She has also played for Japan at five World Curling Championships: 2004 (7th), 2005 (9th), 2007 (9th), 2008 (4th) & 2010 (11th).
After playing for the Meguro rink from 2007 to 2010, Motohashi began skipping her own team in 2011.
She has yet to represent Japan internationally as a skip on the senior level Motohashi graduated from Nippon Sport Science University.
Her nickname is "Marilyn" named after her first name.