Meysam Salehi scored 20 points for Iran and Nishida, Ran and Ishikawa collected 14 points each for Japan, Tehran Times reported.
Team Melli are scheduled to play Brazil on Thursday.
16th-placed Iran will also take on both 14th-placed Bulgaria on Friday and 15th-placed Turkey on Saturday.
The VNL Preliminary Phase features three competition weeks per gender, with each of the 16 teams playing 12 matches. The seven best-ranked national teams in the Preliminary Phase will join hosts Poland for the Finals, which will be held in Lodz from June 27 to 30.
MNA