Reading Japanese Floor Plans: 1R, 1K, 1DK, 1LDK (And What They Really Mean)

By Ibuki — Affarah Friendly Homes · 2025-08-20

Reading Japanese Floor Plans: 1R, 1K, 1DK, 1LDK (And What They Really Mean)

If you’re apartment hunting in Japan, the floor plan matters more than the photos. Photos can hide noise, hide a tiny kitchen, or make a room look bigger than it is. The floor plan, on the other hand, tells you how the space actually functions: where you sleep, where you cook, how you enter, where the balcony is, and what the “real” usable rooms are.

This guide will help you decode Japanese layouts quickly, even if you don’t read Japanese.

1) The code, in plain English: number + letters

Japanese layouts are usually written like 1K, 1LDK, 2DK, 3SLDK.

The number = how many separate “rooms” (usually bedrooms / living rooms), excluding bathroom/toilet
The letters = what kind of shared space exists (Kitchen, Dining-Kitchen, Living-Dining-Kitchen, etc.)

SUUMO’s housing glossary explains this number + alphabet pattern and gives common examples like 1R, 1K, 2DK, 3LDK.

2) What the letters actually mean (K / DK / LDK)

Here’s the practical meaning of each label you’ll see most often:

R (Room): one open space including the kitchen area (a “one-room” studio)
K (Kitchen): a separate kitchen space exists (usually separated by a door/partition)
DK (Dining Kitchen): kitchen + dining space (enough space to eat at a table)
LDK (Living Dining Kitchen): kitchen + dining + living space (room to relax, not just eat)

The key detail most foreigners don’t know:

There are industry advertising rules that provide minimum size guidelines (in tatami) for when an agent can label a space as DK or LDK, depending on how many other rooms exist. The Fair Competition Code enforcement rules set “minimum guideline” sizes like:

If there’s 1 room: DK ~4.5 tatami, LDK ~8 tatami
If there are 2+ rooms: DK ~6+ tatami, LDK ~10+ tatami
(These are ad-labeling guidelines, not a promise of comfort.)

3) Quick cheat sheet: which layout fits which lifestyle?

Use this as a first filter (you’ll still check m² and the plan itself after).

Layout	What it usually feels like	Best for
1R	One open room + kitchenette	Very budget-focused solo renters
1K	Bedroom separated from kitchen	Solo renters who cook or want privacy
1DK	Bedroom + dining kitchen	Solo renters who want a “table space”
1LDK	Bedroom + living/dining/kitchen	Couples, WFH solo, “space to breathe”
2DK / 2LDK	Two rooms + shared area	Couples who need separate rooms, small families

💡 Tip: Don’t choose 1LDK just because it sounds “bigger.” Some 1LDKs are basically a large room with sliding doors. Always inspect the plan for how separable the rooms actually are.

4) The “S” you’ll see in 1SLDK / 2SLDK (and what it is)

Sometimes you’ll see S or +S (e.g., 2SLDK). In SUUMO’s glossary, S is a “service room” (often a storage room or den) that may not qualify as a full bedroom (for example, due to window/opening requirements).

In practice, S often functions as:

a small office
a walk-in storage room
a “guest room” in real life (even if not labeled as a bedroom)

5) Tatami “jo” (帖 / 畳) vs square meters: don’t get tricked

Japanese listings often describe room sizes as 帖 / 畳 (“jo”). Here’s what matters:

For real estate advertising, 1 jo must be at least 1.62 m² under the Fair Competition Code enforcement rules.
That means 6 jo is at least about 9.72 m² in ad terms (6 × 1.62).
But “jo” is still a guideline, and actual tatami sizes can vary by region and building—so you should rely on m² when comparing properties.

ℹ️ Info: Treat “jo” as a quick mental picture, but compare apartments by total floor area (m²) for accuracy.

6) The symbols that matter on Japanese floor plans

Once you can read the code (1K / 1LDK), the next skill is scanning the plan for symbols that affect daily life.

Here are the ones you’ll see constantly:

UB (Unit Bath): a prefab bathroom unit; sometimes “2-point” (bath + sink) or “3-point” (bath + toilet + sink). SUUMO explains UB and why it’s used in rental listings.
WC: toilet
CL: closet
WIC: walk-in closet
PS: pipe space (plumbing shaft; you can’t use it for storage)
MB: meter box (utility meters; also not usable storage)

SUUMO’s plan-symbol guide covers several of these (including PS and MB) and what they mean on diagrams.

Two scanning habits that save you from bad rentals

Look at the “wet area cluster” (kitchen/bath/toilet)
If everything is squeezed into the entry corridor, your living space might be nicer—but your kitchen might be tiny.
Look at doors and separations
Sliding doors can be great, but sometimes they mean your “separate bedroom” is basically part of the living room.

7) A simple checklist before you book a viewing

Before you spend time visiting, make sure the plan passes these checks:

Can you fit a bed and still walk around it? (look at room shape, not just jo)
Is the kitchen separated from the sleeping area (1K+) if you cook often?
Is there real space for a desk if you work from home?
Do you have enough storage (CL/WIC/SIC), or will your room become a closet?
Is the balcony placement useful (light, laundry, airflow), or blocked?

Floor plans are not just “layout.” They’re a prediction of your daily routine.

8) How Affarah helps you read plans like a local

Most people can learn the letters quickly. The harder part is translating the diagram into real-life comfort: the desk, the cooking, the storage, the noise flow, and whether the bedroom is truly separate.

Affarah helps by:

Turning your lifestyle into a “must-have plan checklist”
Filtering out layouts that look fine online but don’t work for your daily routine
Explaining symbols and tradeoffs in plain English before you waste time on viewings