～さ
Turn an adjective into a noun naming a quality
You'll be able to change adjectives into nouns for qualities such as height, strength, or convenience.
芽衣は木の高さを測っています。
mei wa ki no takasa o hakatte imasu.
What do you think this sentence means?
Mei is measuring the height of a tree.
Name a quality
～さ turns a description into the name of a quality. You can measure a height or discuss how convenient something is. The result behaves like a noun, so particles attach after さ.
この荷物の重さは三キロです。
kono nimotsu no omosa wa sankiro desu.
The weight of this luggage is three kilograms.
Form and use ～さ
Remove the final い from an い-adjective, or use the な-adjective stem. いい becomes よさ. Use this for a degree or property; do not assume every adjective produces an equally common noun.
この荷物の重さは三キロです。
kono nimotsu no omosa wa sankiro desu.
The weight of this luggage is three kilograms.
この町の便利さが好きです。
kono machi no benrisa ga suki desu.
I like the convenience of this town.
飛行機に乗る前に、かばんの重さを調べました。
hikouki ni noru mae ni, kaban no omosa o shirabemashita.
Before getting on the plane, I checked the weight of my bag.
部屋を選ぶときは、広さが大切です。
heya o erabu toki wa, hirosa ga taisetsu desu.
When you choose an apartment, its size is important.
富士山の高さを知っていますか。
fujisan no takasa o shitte imasu ka.
Do you know the height of Mount Fuji?
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