The tournament is being played for the fifth occasion with Kenichi Kuboya the defending champion after he defeated, amongst others, Brad Kennedy last year.
The event carries a purse of Ã‚Â¥150 million with the winner to receive Ã‚Â¥30,000,000 or A$375,000.
Only Korean Kyoung-hoon Lee amongst the leading five money winners is missing from this week's field, that list headed by Hiroyuki Fujita and Australian Brendan Jones.
Fujita has won three times this season and finished runner-up in this event in 2008 after leading into the final round.
Jones has played the event on three of the four previous occasions and has played well when he has done so. He has twice been inside the top ten and once 11th. Jones surprisingly missed the cut last week but should bounce back.
Other Australasians in the field are Brad Kennedy, Kurt Barnes, Paul Sheehan, David Smail, Neven Basic and Gareth Paddison. Paddison has an invitation to play the event.