Upvote:1
As stated by Timatic, the database used by airlines:
Visa required, except for Nationals of Philippines with a visa issued by Australia, Austria, Belgium, Canada, Cyprus, Czech Rep., Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland (Rep.), Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Netherlands, New Zealand, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, USA or United Kingdom if in transit through Korea (Rep.) [for max 30 days].
Japan is not in the list. So unfortunately, you do need a visa