In the end, the Red Sox apparently decided to spend more than $100 million to get the Japanese pitcher Daisuke Matsuzaka in a Boston uniform for the next six seasons, a daring financial outlay for an athlete who has never thrown a pitch in the major leagues or sampled the mildly insane rivalry between the Red Sox and Yankees.

For intrigued baseball fans in the United States, Matsuzaka’s relevant statistics are no-brainers: 26 years old, 6 feet, 187 pounds and a 108-60 record with a 2.95 earned run average in eight seasons with the Seibu Lions.

But what many fans, the Red Sox front office and even Matsuzaka’s determined agent, Scott Boras, may not realize is that in the eyes of the Japanese, Matsuzaka’s most revealing statistic might be his blood type, which is Type O. By Japanese standards, that makes Matsuzaka a warrior and thus someone quite capable of striking out Alex Rodriguez, or perhaps Derek Jeter, with the bases loaded next summer.

In Japan, using blood type to predict a person’s character is as common as going to McDonald’s and ordering a teriyaki burger. The association is akin to the equally unscientific use of astrological signs by Americans to predict behavior, only more popular. It is widely believed that more than 90 percent of Japanese know their blood type.