Japanese futon
You could also explain further :
Futons are traditional Japanese bedding. A futon is a padded mattress, called a shikibuton, a quilt, called a kakebuton, and a pillow filled with beans, called a makura. The futon was put on the floor at night for sleeping. They could be easily rolled up during the day when they were not needed.
Japanese traditional bedding
This is also appropriate for describing this kind of bedding.You can also explain the differences between the Japanese futon and the Western futon.
This is called a "Futon" or you can call it a "Japanese Futon" if you want to emphasize its origin.
The Futon is originally from Japan. It is a padded mattress with no springs. It can be rolled up or folded into two.
そのまま”Futon" と言うか、起源を強調したいなら”Japanese Futon" (日本の布団）と言えます。
The Futon is originally from Japan. It is a padded mattress with no springs. It can be rolled up or folded into two. （布団は日本発祥のスプリングの入っていない、パッド入りマットレスです。丸めたり、二つに畳んだりすることができます。）
というように追加説明をしてあげても良いでしょう。
The word 'futon is understood in the UK. It is a mattress that is placed on the floor without a bed base. This method of sleeping is not popular in the UK as most people prefer a mattress on a raised bed base.
"In this Japanese hotel, all the mattresses are futons placed directly onto the floor."
「futon」はイギリスでも知られています。ベッドフレームなしで、直接床に敷かれる「mattress（マットレス）」です。イギリスではベッドを好む人が多いので、「futon」はあまり人気ではありません。
In this Japanese hotel, all the mattresses are futons placed directly onto the floor.
（この旅館では、マットレスはすべて「futon」で、直接床に敷かれます。）
Futonでもアメリカでは使われます。しかしながらFutonだけで言ってしまうと、折り畳み式のソファーと勘違いしてしまうかもしれないので Japanese Futonと言えば通じると思います。
説明をして下さいと言われたら、
Futon is a traditional bedding used in Japan. A futon is just like a mattress, but much thinner, and is placed directly on the floor , or tatami mats. ぐらい言えばいいと思います。
A futon is a traditional style of Japanese bedding.
A full futon set consists of a mattress (also called a shikibuton) and a duvet/quilt (also called a kakebuton).
Both parts of a futon set are compliant enough to be aired, folded and stored away.
Traditionally, futons are used on tatami, a type of mat used which is used as flooring material.
An authentic Japaneses Futon... is nothing like the Futon /sofa bed sold in the west!
The traditional Japanese futon mattress is made up of two parts, the “shikibuton” which is like the mattress part of the bed, and the “kakebuton”, which is like a thick duvet or blanketing used to keep you warm.
"There is no Frame"...since is sits on the floor!
The other differences between the western futon (sofa bed) and authentic Japanese futon mattresses are... the Japanese futon is light and flexible enough to be folded 180 degrees to allow for drying on a line. Most western-style futons are too thick and heavy to be able to be completely folded in half.
A Japanese futon is a mattress and duvet set that gets laid on the floor on a tatami, as a bed. This makes it easier to pick up, fold, and air on a daily basis. It is also very easy to store. This also creates space in the room to be used as anything else and not just a bedroom.
Futon を英語で言うとベッドソファーを指すので、Japanese futon を言う方が意味は伝わると思います。説明したいなら、A Japanese futon is like a mattress on the floor with a comforter on top （日本式の布団は床に敷くマットレスのような敷布団に掛け布団）が説明の仕方の一つです。
ご参考になれば幸いです。
[futon]日本語のままが通じます。色んな国で色んな人が布団で寝ていますからもはや世界中に知られている日本語の言葉です。万が一通じない人がいれば下記の説明が通じるはずです。
A futon is a Japanese-style bed. It is a thin mattress that you place on the floor and sleep on. When you wake up, you can put it away in a cupboard.
(布団って日本式のベッドです。床に置いてそのうえに寝る薄いマットレスです。朝起きるとき押し入れに入れることが出来ます)
I have to get used to sleeping on a Japanese futon.
I put my futon outside in the fresh air every morning.
I am very comfortable when I sleep on my futon and tatami mats.
布団 futon
布団で寝るのに慣れなきゃ。
I have to get used to sleeping on a Japanese futon.
私は毎朝新鮮な空気の中で外に布団を置きました。
I put my futon outside in the fresh air every morning.
布団と畳の上で寝るときはとても快適です。
I am very comfortable when I sleep on my futon and tatami mats.
「布団」はfutonで良いですが、
日本式の布団と言いたければ、Japanese futonと言えば良いですね。
例）
This futon is very comfortable.
「この布団はとても快適だ」
I want to sleep on the futon.
「布団で寝たい」
以上です。
少しでも参考になれば幸いです(*^_^*)
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