OGA, JAPAN (REUTERS) - As a child, Mr Tatsuo Sato was terrified when the Namahage demons roared into his northern Japanese house every year, but in adulthood, he mourned as the centuries-old tradition faded away.
"The kids disappeared, the young people disappeared. We had to give it up," Mr Sato, 78, said of the New Year's Eve visits by men in horned masks and straw capes, all shouting "Are there any bad kids here?"
Unesco registering Namahage as a cultural property late last year has given new life to the colourful tradition.
But experts say the recognition, which included several similar traditions in which costumed "gods" visit villages, doesn't automatically guarantee survival.
In some cases, it could even stifle changes that help keep the groups going, such as including outsiders or women.
"Within this Unesco designation, there are several groups that I believe may not be able to continue - or not be able to continue in their present form," said cultural history professor Satoru Hyoki of Tokyo's Seijo University.
Masukawa revived its traditional New Year's Eve ritual last year after 12 years, thanks partly to a group of young transplants to the area, whose population has dwindled to just 130 in the last two decades.
Oga had 120 Namahage troupes in 1989, but just 85 in 2015; that only young men were allowed to take part didn't help matters.
Some hamlets have raised the age limit, while others welcomed young outsiders. One of those transplants, Mr Haruki Ito, came up with the idea of inviting young men from around Japan to take part alongside the locals in Masukawa.
"If Namahage aren't young men, it's no good, everyone agrees," said Mr Sato, who took his turn as a demon when he was younger. "Maybe if women did it, we'd have enough people, but I don't think we have to go that far."
Local officials hope the long-sought Unesco designation stirs a tourism-based economic boost badly needed in places like Oga, a remote peninsula some 450 kilometres north of Tokyo, and the Masukawa district where Mr Sato lives.
Economically, the attention has already helped. The Oga city's Namahage Sedo festival, held in early February, drew 7,600 people, compared with 6,100 in 2018.
The festival, in which a parade of torch-bearing demons makes its way down a snow-covered mountain, swells Oga's population by nearly 30 per cent as tourists pour in, hoping straw from the demons' capes - believed to be lucky - will fall near them during the smoky procession.
Masukawa's decision to revive its New Year's Eve tradition, buoyed by the Unesco registration, led to a scramble for everything from straw to makeshift sword materials foraged from local discount stores.
The flurry of activity made people "really happy", said Mr Ito, 27, adding that some elderly residents told him the revival literally gave them reason to live.
"Many people feel 'the gods must really care about me'," he said.
Prof Hyoki said the Unesco designation has no money attached to it and carries the risk of unsustainable tourism or even a loss of autonomy.
Unesco recognises that traditions change, but the Japanese registration required to apply for the listing does not, which he said creates misunderstandings.
"Some people worry that if they got the Unesco listing, they'd just be forced to continue in the traditional ways, that if they try to change things people will say, 'that's not the way it was done in the old days,'" he said.
For now, Oga has parlayed growing interest into a year-round promotion of everything Namahage, including demon-themed biscuits, rubber stamps and even a facial skin mask.
Many are designed by Ms Kokoro Ohtani, a 24-year-old from southern Japan who moved north for university and fell in love with the Namahage. She now works at the Oga town office.
Ms Ohtani, who is close to one troupe of Namahage performers, said respect for her friends and their reverence of traditional ways has deterred her from pressing to take part.
"There's a bit of a clash within me, but it isn't discrimination or chauvinism," she said.
"It's more like feeling I want to keep trying so that, one day when they let women take part, I will be the one they choose."