TOKYO (Kyodo) -- Nippon Professional Baseball on Friday notified its 12 clubs that players can use so-called torpedo bats in regular-season games.

NPB's rules committee made the decision, effective the same day, after confirming that the torpedo-shaped bats, which have taken Major League Baseball by storm this season, do not violate any rules.

Torpedo bats widen out into the barrel and get thinner again toward the end of the bat, drawing comparisons to a bowling pin.

"It's not against the rules. No problem at all," said Masato Tomoyose, one of the committee members.

According to The Associated Press, when the New York Yankees smashed a franchise-record nine home runs in a 20-9 rout of the Milwaukee Brewers on March 29, five players homered with torpedo bats, including Paul Goldschmidt, Cody Bellinger and Anthony Volpe.

Two days later, Cincinnati Reds shortstop Elly De La Cruz homered twice when he used a torpedo bat for the first time.