Type a hotel + dates once → open a search on every site, including the Japanese ones.
What this does: opens a ready-to-go search on each booking site (it doesn't fetch or scrape prices). The real value vs. Google Hotels is the Japanese sites 🇯🇵 (Rakuten, Jalan, Ikyu) where ryokan inventory & deals hide. Booking / Agoda / Trip / Rakuten carry your dates automatically; Google / Jalan / Ikyu open a search that lands on the hotel's page, where you set dates (their sites can't be reliably deep-linked with dates).
Or — area discovery 🗺️
For the "any room in this area for these dates" case (e.g. the Nebuta hunt) — and for finding apartments for the slow, cook-your-own-food stays. Set your dates above, then pick an area: Jalan & Ikyu open real dated area searches, the OTAs search the area name, and Airbnb & Vrbo 🏠 are added for homes/apartments (Airbnb auto-applies its monthly discount at 28+ nights).
Tip: if “Open all tabs” only opened one site, your browser blocked the pop-ups — allow pop-ups for this page once, then try again.