Japan wasted an early lead on Saturday in a 57-22 women's test defeat to seventh-ranked Ireland.
On the same Shizuoka Stadium Ecopa pitch where the Brave Blossom's won a historic victory over Ireland in the men's 2019 Rugby World Cup, 13th-ranked Japan opened the scoring on tries by Misaki Suzuki, in the third minute, and Komachi Imakugi, in the sixth.
Ayasa Otsuka converted one try and put the hosts up 15-0 with her 11th-minute penalty goal, but six unanswered Ireland tries, including a hat-trick from Neve Jones, sealed Japan's fate.
The two-test series, a warmup for the Women's World Cup in New Zealand starting in October, will conclude next Saturday at Tokyo's Prince Chichibu Memorial Rugby Ground.