When buying property in Japan, almost regardless of the type of building, the unit is usually handed over to the new owner already fitted out, including the interior partitioning and equipment such as the kitchen and bathroom. Most Japanese properties are essentially move-in ready. Because of this, Japanese buyers and renters pay particular attention to a unit’s layout and fittings, since these directly affect a property’s value and rental potential. This article explains the terminology used for Japanese apartment layouts, along with some common fittings you should know about.
Different Terminology: LDK
In many markets, apartments are described by counting bedrooms — a “one-bedroom” or “two-bedroom” apartment, for example. In Japan, layouts are instead described using a number combined with letters, in the format nLDK. Here, n is the number of bedrooms in the unit; R stands for Room; K stands for Kitchen; D stands for Dining Room; and L stands for Living Room. What some markets would call a “one-bedroom” apartment is called 1LDK in Japan, and a “two-bedroom” apartment is 2LDK. Japan’s most common “1R” layout means the bedroom is not separated from the kitchen and living area; “1K,” by contrast, means the kitchen is separated, with the bedroom and living area sharing the same space.
Layout and Floor Area
Generally speaking, 1R is the smallest layout — just a single room with the kitchen inside it, with a floor area of roughly 10-20 sq. m, comparable to what some markets would call an open-kitchen studio. 1K is a bit larger, with the kitchen and bathroom separated from the bedroom into a different space. 1DK has an even larger kitchen, with enough room for a dining area. 1K and 1DK units are typically around 20-30 sq. m. 1LDK is what would generally be understood as a one-bedroom-with-living-room unit, generally 40 sq. m or larger. That said, in Japan there is no fixed relationship between a unit’s floor area and its layout code, so when buying, look carefully at exactly which layout type is being described.
Japan’s Unit Bath System
Bathrooms in Japan work differently than in many other markets. Because Japan’s climate is cold, most Japanese people enjoy soaking in a bathtub, so a bathtub is considered standard equipment in a Japanese home. Japanese housing culture also tends to treat the bathroom and the toilet as two separate spaces, so in many units the two are kept apart. Generally speaking, only older buildings tend to combine the bathroom and toilet into one space; most newly built units keep them separate.
In addition, Japanese bathrooms are mostly prefabricated “unit baths,” which follow standardized specifications. Floor plans will typically mark the unit-bath size using a code such as 1116, 1216, 1317, 1418, 1620 or 1822. The first two digits represent the length, and the last two represent the width — so 1418 means a bathtub 1.4 meters long by 1.8 meters wide. As a general guideline, a household of two or more bedrooms should look for a bathtub size of at least 1418, though many newly built 1K studio units now come with a smaller 1116 size. Because Japanese bathtub sizes are standardized at the design stage, it can be difficult, or in some cases impossible, to change the bathtub size afterward — so it is worth paying close attention to this measurement before investing in a property.
A Notable Feature: Reheating Function (Oidaki)
Finally, one more valuable detail about Japanese bathrooms: when choosing a new or rented home, Japanese buyers and tenants often specifically look for a bathtub with a “reheating” function (oidaki). This means automatic temperature maintenance. The Japanese pay close attention to everyday comfort and enjoy soaking in the bath, so unlike in many other markets, where the bathtub is filled by manually adjusting the hot and cold taps, a Japanese unit bath lets you preset the water temperature and volume on a wall-mounted control panel, then start the bath with a single button, without any manual adjustment — and the system can keep recirculating and reheating the water to maintain that temperature. Homes with this reheating function are generally more popular with tenants in the rental market.
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