In Japan rooms are divided by layout type : 1K, 1R, 1DK, 1LDK, 2K, 2R, 2DK...
Japanese apartment layout are usually very similar, there isn't a huge diversity.
1R 1 room non separated with the kitchen. (1 Room)
1K a kitchen + 1 room (1 Kitchen)
1DK a dinning/kitchen room + 1 room (1 Dinning Kitchen)
1LDK a dinning/living/kitchen room + 1 room (1 Living Dinning Kitchen)
2K a kitchen + 2 rooms (2 Kitchen)
2DK a dinning/kitchen room + 2 rooms (2 Dinning Kitchen)
2LDK a dinning/living/kitchen room + 2 rooms (2 Living Dinning Kitchen)
3LDK a dinning/living/kitchen room + 3 rooms (3 Living Dinning Kitchen)