A parent who had just come back from a trip put it plainly: the AI gave them a route, they followed it, and the restaurant it sent them to had closed down. Another travel writer named the mechanism in one line — tools built on static training data miss closures and price changes, every time.
That is not a Japan problem in itself. What is particular to Japan is where the answer lives.
Closing days are often decided one month at a time
An English page will tell you a place is “closed Wednesdays”. That is frequently not how it works.
Shikairou in Nagasaki — the restaurant where champon was invented — closes roughly two Wednesdays a month, and which two is announced month by month on its own site. The notice posted on 1 August 2026 reads, in full:
8月の休業日⇒ 8/5（水）・8/19（水） 9月の休業日⇒ 9/2（水）・9/16（水）
August closing days: the 5th and the 19th. September: the 2nd and the 16th.
Nothing about “closed Wednesdays” would have told you that the other three Wednesdays are fine. And nothing dated earlier than 1 August could have told you about September.
It runs the other way too. The National Museum of Nature and Science in Tokyo is closed on Mondays — except that it opens every day in August, which the official page states outright. A guide that learned “closed Mondays” and stopped there sends a family away on a day the museum is open.
The thing you booked the day around can be cancelled with three days’ notice
Ryugado Cave in Kochi runs a projection-mapping show inside the cave. On 5 August 2026 the cave posted that the show was cancelled from the 8th to the 16th — a nine-day gap over the busiest family week of the year, announced three days ahead, in Japanese only. The same notice board carries entries like 「８月１５日（土）本日の営業について」 — about today’s operation, Saturday 15 August — posted the morning it applies.
Here is the part that matters most, and it is nobody’s fault: the cave’s own English pages have no notice board at all. They describe the cave’s attractions — and among them, “a projection mapping exhibit which fuses the ancient with the technological future”. A family reading the official English site in the second week of August 2026 is being told about a show that is, on that same site’s Japanese side, cancelled.
Keeping a notice board current in several languages is genuinely hard, and not every venue manages it. We looked at three. Ryugado Cave’s English pages have no notice board at all. The National Museum of Nature and Science has a “News” link but nothing dated on the page itself. The Cup Noodles Museum in Osaka Ikeda does carry dated English notices — including one from 25 July 2026 about Obon parking and its numbered-ticket distribution.
So this is not a rule. It is the thing to check first, and it takes ten seconds: if the English page carries no dated notices, the Japanese page is where the news is.
What to do about it
Before a day you have built around one place, open the official site and find its notice board. It will be labelled お知らせ or 新着情報, usually on the front page, and it is where closures, cancellations and price changes appear first. Your browser will translate it well enough — the dates and the numbers are the part that matters, and those need no translation.
Three specific things worth looking for:
- This month’s closing days, if the place does not use a fixed weekday. Look for 休業日 or 定休日 followed by dates.
- A notice newer than whatever you are reading. If the guide you are using is from last spring and the site posted something last week, the site wins.
- The date on the notice itself. A page with nothing newer than two years ago is telling you something too.
What we do
Every family fact on this site carries the link to the official page it came from and the date we last opened that page. When we wrote up Ryugado Cave we found the projection-mapping cancellation on the official notice board and left the show out of the page entirely, because a family cannot rely on it this month.
That is the whole method: read the notice board, write down the date, and leave out the things that will not be there when you arrive. You can do exactly the same in about two minutes per place — and on the days when it matters most, it is worth doing yourself as well.