Japan had 14 hits, including a three-run homer by Ayane Nakagawa. Sakura Miwa and Mio Sakamoto allowed just one hit. The only other Puerto Rico runner reached on an error.
The Olympic Champions scored early and had a 14-hit game, including a three-run home run by Ayane Nakagawa. Sakura Miwa allowed just a runner on an error, and her reliever, Mio Sakamoto, allowed another one on a base hit.
Japan wasted no time getting to Puerto Rico's starter, Taran Alvelo. Shortstop Kyoko Ishikawa reached on a one-out infield hit, and left fielder Hotaro Tsukamoto followed with a base hit, bringing her to third. Japan got on the scoreboard with a double steal. Alvelo loaded the bases on a walk and a hit batter. Shito Suto made it 2-0 with a sacrifice fly.
Catcher Yuma Kiriishi reached on a one-out double in the top of the second. Leadoff hitter Ayane Nakagawa singled and brought to third. With Ishikawa running at third for Kiriishi and one out, Japan attempted another double steal, but Nakagawa was tagged for the third out and Japan's second at-bat went scoreless.
A rare Japanese defensive error gave Puerto Rico the leadoff runner in the bottom half of the frame. It would be the only runner allowed by Sakura Miwa, who got out of the inning by striking out the side.
Japan put runners at second and first with one out in the top of the fourth on back-to-back infield singles by pinch hitter Urara Fujimoto and Kiriishi. Nakagawa worked the count full, then homered on the sixth pitch to open the score to 5-0.
Ishikawa's triple sent Alvelo to the showers. Tsukamoto welcomed reliever Gianna Mancha with a base hit, extending Japan's lead to 6-0.
Mio Sakamoto relieved Miwa in the bottom of the fourth.
Japan added two runs in the top of the fifth on base hits by Ishikawa and pinch-hitter Haruki Sumitani to extend the lead to 8-0, enough to end the game in five innings
.Japan will open Day 3 at 11:00 against No. 8 Netherlands. Puerto Rico, facing elimination, will play No. 10 Australia at 16:30. All times are local.