The Nippon Ham Fighters’ new ballpark, Es Con Field Hokkaido, due to open next spring, does not meet Nippon Professional Baseball’s rules for the distance from home plate to the stands, a source with knowledge of the matter said Tuesday. The net in front of the first row of seats behind home plate is required to be at least 60 feet (18.288 meters) from the base, roughly three meters farther away than the new park’s stands. The issue was brought up by NPB’s executive committee. On Thursday, the team declared the park, with a retractable roof that will protect its natural grass surface from Hokk…