Yuwaku Onsen is a 1,300-year-old hot-springs resort tucked between mountains along the Asano River south of Kanazawa. Ten mid-size traditional inns line its slim main street, leading to a small hillside shrine and a man-made pond.

Earlier this month, I shuffled behind a procession of lantern-bearing priests and local residents in yukata (summer kimono) for the town's seventh annual Bonbori Matsuri (lantern festival). Some 15,000 other tourists joined me.

We weren't there for the inns, which had been booked months ago. The one-day Bonbori Festival has become Yuwaku's biggest draw. Six hundred attended the first event in 2011; this year's numbers are 25 times that. Local officials peg the town's single day's earnings at more than $100,000. Not a windfall, but a boost to a rural economy in Japan's aging and neglected hinterlands.