Floor/storey abbreviations in Japan
I’m noticing that the floor number abbreviations we use here in Japan seems to be specific to Japan, and modified to follow Japanese word order.
Basics
Japan does not start counting from the ground floor, so ground level is the first floor, 1階 (ik-kai), abbreviated “1F”, the “F” obviously standing for “floor”. Then it goes up arbitrarily high: 2階 (ni-kai), 3階 (san-kai), 4階 (yon-kai), abbreviated “2F, 3F, 4F”, and ending with the rooftop floor, 屋上 (okujou), abbreviated “R” ostensibly for “Roof”. (Sometimes the F isn’t there, randomly.)
Basements
But the underground floors follow a different pattern. The first basement is called 地下1階 (chika ik-kai, “underground first floor”), and abbreviated “B1”, or just “B” if there is only one underground floor. Why is the “B” for “Basement” before the number, when the “F” was after the number? It’s probably to match Japanese word order.
Mezzanines
And then mezzanines kinda just wreck the pattern set up by the overground and underground floors.
I can’t find an English consensus online whether the mezzanine above the first floor should be called “the first mezzanine” or “the second mezzanine”, but Japanese has a firm consensus: the mezzanine between the first and second floors is 中二階 (chuu ni-kai, “middle second floor”).
So now you’re thinking, “Okay, we’re using English initials to represent the corresponding Japanese words. So ‘M’ for ‘Mezzanine’, ‘2’, then ‘F’ for ‘Floor’, right?” Wrong: it’s “M2” without the “F”.
ALSO, THERE IS NO “M1”! The mezzanine between the first basement and the first floor is 中地下1階 (chuu chika ik-kai “middle underground first floor”) “MB1” or 中地階 (chuu chi kai “middle [under]ground floor”) “MB”.
At least that’s what Wikipedia says, but this building has an MB floor between B2 and B1 because OF COURSE it does.
It was bad enough that we have an off-by-one error between the 1st basement and the 1st floor. Mezzanines have an off-by-two error! Between the 1st basemezzanine and the 2nd mezzanine! And only sometimes!
Anyway, is there an established system where you live, or does it all seem just ad-hoc? Personally, I like that Japan has a standard set of abbreviations for floors and mezzanines, but I hate how they work.
















