mileage run; travel hacking
Colloquial term for deliberately taking flights or using credit cards to accumulate frequent flyer miles, often with a humorous or self-deprecating tone.
週末に沖縄までマイル修行に行ってきた。
I went on a mileage run to Okinawa over the weekend.
彼はマイル修行のためにクレジットカードを何枚も作っている。
He has opened several credit cards just for travel hacking.
Compound of マイル (mile, frequent flyer mile) and 修行 (training, ascetic practice). The term humorously frames the effort of earning miles as a form of rigorous training.