It sure is.
From the very first pitch of the bottom of each inning, the fans packing sections 1 and 3 in the bleachers in right field and right center are up and at it. They are led by a cheerleader who stands in the first row beyond the wall, wields a whistle, and leads the crowd, most of them bedecked in Giants jerseys of their favorite players, into chants and songs.
"The songs kind of just say the players' names and have a little bit of a cheer for them to tell them to do good things in the game," said Ryuichi Kuramochi, a Tokyo-based businessman who was at Sunday night's exhibition between the Giants and the Oakland A's with his 12-year-old son, Tatsuya.
"It's kind of slow and it's very loud and the chants say things like, 'Be aggressive,' or 'Please get a hit.'"
Kuramochi said he lived in North Carolina for a while and would go to Atlanta Braves games. He said he could never figure out why American fans are so comparatively mellow.
"I don't know," he said with a smile. "Maybe it's just strange Japanese culture."
Don't tell that to Dan Snyder. The 46-year-old Texas native was hanging out by the concession stand, having an adult beverage and soaking in the atmosphere. Snyder is in Japan working as a marine machinist on a nearby ship, and he can't get enough of this game and this place.
"The fundamentals are pretty much the same, but the cheering ... I love the Japanese folks," Snyder said. "They're pretty cool. And they're not throwing things at the field. They're not quite as rowdy, but their little cheerleading section in the corner is pretty cool."
It was so cool on Sunday night that it might have made fans for life out of two guys who had never been to a baseball game before.
Etienne Piketty, 20, and Gabin Tellenne, 21, are journalism students from Paris who are interning for a magazine called Les Inrockupitibles. They were sent to Tokyo, all expenses paid, and told to come up with stories on "funny things to do in Tokyo." They heard about the ballgames here, bought tickets for Sunday night, and had to laugh when they found themselves sitting directly behind one of the guys playing the trumpet in the Giants Cheering Club.
"In France, baseball is not very popular," Piketty said. "We don't know the score, we don't know the rules, we don't know anything. We just want to see Tokyo the city."
They're seeing it in all its enthusiastic, baseball-crazy glory, and they might just be catching the fever, too.
"Every sport should be like this," Piketty said. "Everybody is excited. There is real ambience here."