Reading Japanese Apartment Listings: 1K, 1LDK, Jo, UB and the Layout Codes
Updated: 2026-09-11
Quick answer
Hi, I'm Miya, your GetConnectedJapan guide. Japanese rental listings look like a puzzle at first: strings like 1K or 1LDK, room sizes written in jo, and abbreviations like UB. None of it is secret code once you know the pattern, and this guide walks you through the pieces so you can picture a home before you ever step inside.
The short version: a number tells you how many rooms there are, and the letters after it (L, D, K) describe the living, dining and kitchen space. Sizes come in tatami mats (jo) or square metres, and small terms like genkan, oshiire and UB fill in the rest. Read on and the next listing you open will make sense at a glance.
The number-plus-letters code
The layout code is a number followed by letters. The number counts the separate rooms you can close off and sleep or work in. The letters stand for shared living space: L is living, D is dining, and K is kitchen. So 1R is a single room where the kitchen sits in the same open space, while 1K is one room plus a small separate kitchen area. 1DK adds room for a small dining table by the kitchen, and 1LDK gives you one bedroom plus a combined living-dining-kitchen area big enough to relax in.
From there it scales up in the obvious way. 2LDK means two separate rooms sharing one living-dining-kitchen space, 3LDK means three, and so on. The letters describe the shared area, not extra rooms, so the difference between 1DK and 1LDK is mostly how much floor space that combined area has. Once you see the pattern, the code alone tells you roughly how the home is carved up.
Sizes: jo and square metres
Room sizes are often given in jo, meaning the number of tatami mats that would fit. One mat is a rough unit of area, so a 6-jo room is a common, comfortable single bedroom and a 4.5-jo room is noticeably cosier. Even in a modern flooring apartment with no actual tatami, listings still measure rooms this way, so it pays to get a feel for what a few jo looks like.
The whole unit is usually listed in square metres as well, covering the total interior floor area. Reading both together helps: the square metres tell you the overall size, while the jo figures show how that space is split between rooms. A larger total with small individual rooms feels very different from a compact total built around one open room.
Bath, toilet and the entryway
One of the most useful abbreviations is UB, short for unit bath. This is a moulded all-in-one bathroom where the tub, shower and toilet share a single waterproof space. Many listings instead advertise basu toire betsu, meaning the bath and toilet are separated into their own rooms, which a lot of people prefer for daily use. Knowing which one you are looking at tells you a great deal about the daily feel of a place.
Near the front door you will find the genkan, the sunken entryway where you take off and store your shoes before stepping up into the home. It is a standard feature, and listings sometimes note its size or shoe storage. Small details like this shape how a home actually lives, so they are worth reading rather than skimming.
Storage, balcony and orientation
Storage terms come up constantly. An oshiire is a deep built-in closet, traditionally used for storing folded futons and bedding behind sliding doors, while a Western-style closet is often listed as such. Most homes also have a balcony, and listings note whether laundry can be hung there. These features decide how much of your own furniture you will need to buy.
Orientation matters too. Minami-muki means the home faces south and tends to get more daylight through the day, and you will see other directions noted the same way. Listings usually give the building's age or construction year as well, which hints at insulation, layout style and fixtures. Together, orientation and age round out the picture the layout code started to draw.
Househunting happens on your phone
Here is the practical part: almost all of this reading happens inside property apps. You browse listings, open floor plans, save favourites and book viewings straight from your phone, and agents increasingly expect to reach you by call or message to confirm a time. A Japanese mobile number and a working data plan turn househunting from something you do at a desk into something you can do while you are out looking.
That is why sorting out connectivity early makes the whole search smoother. With Rakuten Mobile you apply online using your residence card, and eSIM-capable phones can connect the same day, often in around fifteen minutes, so you are reachable from the listing stage onward. Set it up once you have arrived and are ready, and the rest of your househunting can run entirely from your hand.
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