Shuichi Furukawa drove in the winning run in the top of the 13th inning Tuesday as tournament debutant Seiho denied Aikodai Meiden a spring-summer double with a 4-2 upset victory in the national high school baseball tournament.
Furukawa delivered a two-out, two-run single that broke a 2-2 deadlock and moved his Nagasaki school into the second round of the annual tournament at Koshien Stadium.
In Tuesday's other first-round games, Ehime's Saibi, runnerup in last year's championship, scored five runs in the first inning en route to a 6-0 shutout of Asahikawa Kogyo from Hokkaido.
Ube Shogyo of Yamaguchi Prefecture also cruised into the second round with a 7-4 victory over Niigata Meikun, with Ryosuke Kudo, Yuma Emoto and Hideo Toyota delivering three hits in a 20-hit attack.
First-timer Seisei Kogyo of Shizuoka Prefecture turned a two-run deficit into a 5-3 lead with a four-run rally in the third inning and held on to beat Shimane's Gonokawa 8-5.