The Mizuno Open(ミズノオープン?,Mizuno ōpun) is a golf tournament played in Japan since 1971. It has been a Japan Golf Tour event since 1979. Beginning in 1998, the top four finishers in the Mizuno Open that were not already exempt into The Open Championship received exemptions. There is also a mini-money list of events up to and including the Mizuno Open that earns two exemptions to The Open. This is why the event has been called Gateway to the Open(全英への道?,Zen'ei eno michi) since then. It was played at the Setonaikai Golf Club in Okayama from 1998 to 2006 and also from 2011 to 2014 and at the Tokinodai Country Club in Ishikawa from at least 1985 to 1997. The purse for the 2015 event was ¥100,000,000, with ¥20,000,000 going to the winner.
From 2007 to 2010 The Mizuno Open merged with the Yomiuri Open to form the Gateway to the Open Mizuno Open Yomiuri Classic. It was played at the Yomiuri Country Club in Nishinomiya, Hyōgo.