When Tsutomu Ito comes to bat, Iwaguchi goes to his music stand and flips to the song written just for the Lions' catcher, then launches into the new tune.
Around him, thousands of other fans sing their fervor in chants, claps, dances, cheers, coordinated arm movements, and -- most often -- by banging plastic megaphones in time while chanting: "Ito, get a hit!"
In the left-center stands, thousands of mirror images, wearing orange and yellow jerseys, smocks, caps and headbands, are just as incessant whenever the rival Tokyo Yomiuri Giants are at bat.
In the United States, Major League Baseball's World Series in October has been canceled for the first time since 1904 by a players' strike.
But the Japan Series, the season-ending baseball championship, is in full swing.
The series has gripped much of Japan, nowhere more so than at the sold out 37,000-seat Seibu stadium.
Iwaguchi, a stocky 26-year-old, has been a Lions fan since they moved here to Tokorozawa 16 years ago.
"The players say that it's because we're rooting for them they can give their best," he says. "During the regular season there's always tomorrow, but now you've got to win four games or that's it."
The Giants took the game Tuesday 2-1 in 10 innings in the first Japan Series night game in 30 years. The Giants lead the best-of-seven series two games to one. Once-complacent baseball officials, reportedly edgy over the popularity of the Japan soccer league started last year, said they wanted as many people as possible to watch the games on TV.
High school senior Keita Kawasaki, like Iwaguchi, bought and learned to play his trumpet just to root for his team, only his team is the Giants, who have never beaten Seibu in three Japan Series tries.
"Anyone playing the Giants is the enemy, but Seibu is special," says Kawasaki, who sports dyed-brown hair and an earring as well as the same Giants jersey as eight fellow trumpeters, including one woman with an infant on her back.
A few of them look tipsy, and it's no wonder, with vendors plying the stands with "beer here" and "whiskey and water!" In the box seats behind home plate, miniskirted young women offer anything from cocktails to $65 steak dinners.
But the biggest lines are at the kiosks selling the $4.50 soba noodles in broth and the $3.50 octopus balls.
Chicago native Sonny Little, 32, a shop worker at the Kaneda U.S. Air Force base in Okinawa, has been coming to Lions games since he was first stationed much closer, in Yokohama, about four years ago.
The food and the fans seemed a bit weird at first, he admits, but now he sees more similarities than differences to the Chicago Cubs' Wrigley Field, two blocks from where he grew up.
"It's fun here cheering and watching all the fans go crazy and the children having fun," he says. "I didn't come to Japan to sit around."
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