Did Japanese people discover Twice had Japanese members 2 comebacks in? Boombayah peaked higher than LoA and Cheer Up on the Billboard Japan charts. LoA had its debut at 89th and was out in a week. Cheer Up at 32nd and was out in 5 weeks. Boombayah peaked at 15th and stayed on the chart for 20 weeks.
Japanese and Korea relations were poor in the early 2010's, Twice got big by having a song go viral not due to the nationality of their members. BP had good support from the start in SEA hence all the YouTube records from debut. Twice didn't have strong support in Japan until they went viral
that's all good but twice didn't have strong support in japan until they blew up in korea with cheer up. those are facts.