Traditional Japanese houses are usually one- or two-storeyed buildings. Historically and geographically Japan has not so much territory that is why living spaces here tend to minimalism both in terms of square meters and interior.
You should take your shoes off at the hall and put them in order that toes pointed to the entrance. If hosts suggest you slippers, be sure to put them on. If you are going to visit a Japanese house it would be better to take a souvenir (tsumaranai-mono in Japanese) because it is considered to be impolite visiting without a gift. Alcohol, chocolate or any traditional souvenir from your country would go well as the gift. There is no tradition in Japan to open gifts right away, so if the hosts make a present to you as a responsive gesture of courtesy do not unwrap it immediately because Japanese would consider this like display of greed and excessive curiosity.
There is a special niche called tokonoma in an every traditional Japanese house. That tokonoma usually contains ikebana and kakemono, a paper roll with a famous saying calligraphically written on it. Referring to one of our previous articles on etiquette and behavior in Japan, please remember that if there is tatami on the floor it is impossible to step on tatami in any footwear.
We have also spoken about two main Japanese postures – seiza (official formal pose) and agura (with one's legs crossed, more informal). There also some rules regarding behavior on tatami. For instance, it is prohibited to sit sprawling and stretching one's legs, especially to touch with feet those present (it is considered insulting to touch someone with one's feet or even turn one's feet to someone). It is worth to comply with the dress code for such occasions: try to avoid shorts, jeans; women should avoid miniskirts, décolleté, bare feet – socks are necessary and better if they are white.
If you are invited to o-furo (this word has two meanings "Japanese baths” and just "bath”) note some nuances. First, before entering the o-furo you should take a shower and the longer you are soaping and washing yourself the better – Japanese will undoubtedly appreciate your knowledge of this rule. They usually soap and washing about thirty minutes before to go into the o-furo or onsen (hot spring). Only after this procedure it is possible to enter o-furo to experience all fascination of relaxing in hot water.
Second, after luxuriating in the o-furo do not pull a plug because the bathtub is filled only once an evening. If you are a guest – no doubt you will be allowed to o-furo first and this is considered as a great sign of attention and honor that is why you need to thank the hosts.