How this is kept
This page sets out how the eighteen entries are chosen, where their statements come from, what is deliberately left out, and how to report an error. It also explains two things that are easy to misread: the winter section, and the compact hotels outside Japan.
How the hotels are chosen
A hotel enters the reference when its building, its plan or its shared rooms can be described from open material without guesswork. The four sections are fixed, and the number of entries in each is fixed as well. Hotels are not chosen for quality, and nothing here is a recommendation.
Which sources are used
Statements come from the hotel's own published material, from mapping, and from press coverage that names its source. Where two sources disagree, the entry is written so that it holds under both, or the detail is dropped. Dates of construction are given only where a source states them.
What is not here
There are no prices, no star grades, no room counts, no reviews, no rankings and no reservation buttons. Hotels are not compared with one another. Weather, availability and access are never promised, because none of them can be promised by a reference.
How to read the winter section
Buildings of ice and packed snow stand for the winter season and are taken down when they melt, then raised again from scratch the following year. Nothing in those entries carries over from one season to the next. Heated buildings on the same sites are described separately, and glass structures elsewhere are not ice rooms at all. Season dates are set by each operator and should be confirmed with the hotel.
Compact hotels outside Japan
Two entries in the first section are ordinary compact hotels rather than berth houses. Their rooms are small and standardised, each with its own door and bathroom, and the entries say so in the first paragraph. Calling such a room a sleeping berth would be wrong, so it is not done here.
Reporting an error
Corrections are welcome and are made rather than argued. Write to the address on the contact page with the entry name and, where possible, the source that contradicts what is written. Entries are amended once the source has been checked.