First of all, several key points of Japanese style: tatami, sliding door, wall storage, wood and Japanese decoration. Floor: the floor is completely made of tatami structure, which is expensive and difficult to maintain. I suggest laying ordinary floors and buying tatami blocks.
Just like this. It's heavy, so it can be laid on the floor, and it's not easy to slide down. You can spread the whole room as a wooden floor, and buy some tatami blocks to cover some rooms, which can be used as beds/chairs, etc.
This room doesn't need a bed and a sofa. If you have a desk, you can put a chair with a log color. Of course, all the chairs are not traditional Japanese elements, just for convenience (it will be uncomfortable to put a low table on the ground when using the computer for a long time).
Walls: Wallpapers with elegant colors can be used for walls, and pure white is not recommended. It is best to be close to the natural color. For example, elegant green, textured beige and so on. Door: If the sound insulation requirements of the room are not too high, it is recommended to use wooden sliding doors. Now there are also businesses in China that can do this kind of door. And it is not expensive. Very Japanese.
Japanese sliding doors are generally lattice-shaped, with paper stuck on them. But the sound insulation is really not as good as ordinary doors. As Deng Hui said, the temperament of Japanese-style rooms has a lot to do with the environment. So if you have a yard on the first floor or the top floor, you might as well open a floor-to-ceiling window facing the yard and plant flowers and plants in it, which will have a special flavor. If there is no such condition, we might as well put some potted plants.
Furniture: Japanese rooms are usually closets, that is, cabinets with holes punched in the walls. The sliding door of the cabinet is flush with the wall. Tatami can be stored in bedding and clothes when sleeping. Very convenient, mainly to save money on materials.
If you are interested, you can set up a wardrobe for storage. But it doesn't hurt to play with a set of ordinary furniture of log color. Buy a beautiful set of bedding. It doesn't matter if you just pile it up.