少年老い易く学成り難し
(Shounen oiyasuku gaku narigatashi;
“For a youth to age is easy, and to become a scholar is hard”)

Definition:

People should study hard when they’re young, because time is precious and fleeting. When you’re young you feel like you have all the time in the world to get stuff done in, but then you’re old before you know it. Seen from another angle, study is hard, so it’s best to get a good head start on any skill or knowledge set that you really want to master. The original context goes on to suggest that even a little study every day adds up over time – hardly a new concept – which perhaps reduces the bleak sense of “not enough time” that the kotowaza on its own may invoke.

Breakdown:

We begin with the noun 少年 (shounen), literally “few years.” The term is most commonly used to refer to boys or young men, but here it refers to young people in a more universal sense. This is followed, with any particles elided, by the verb 老ゆ (oyu), “to age,” in conjunctive form. This allows it to act like a noun, attached to and modified by the adjective 易し (yasushi), “easy.” The adjective is also in conjunctive form, allowing the first clause to connect to the second.

The second clause begins with the noun 学 (gaku), “learning.” Again this is followed, without particles, by a verb – 成る (naru), “to be” or “to become,” again in conjunctive form and again modified by an adjective – 難し (gatashi), “difficult.” This one is in sentence-final form.

Notes:

This saying comes to us from the Ŏu chéng (偶成, in Japanese Guusei), a poem by 12th Century CE Confucian philosopher Zhu Xi (朱熹, Shu Ki).

Example sentence:

「君、宿題は罰などじゃない。少年老い易く学成り難し、毎日少しずつ勉強するのが自分の成長のためだ」　「それなら、ガクになりたくないなら休んでもいいってこと？」　「生意気！」

(“Kimi, shukudai wa batsu nado ja nai. Shounen oiyasuku gaku narigatashi, mainichi sukoshi zutsu benkyou suru no ga jibun no seichou no tame da.” “Sore nara, gaku ni naritakunai nara yasunde mo ii tte koto?” “Namaiki!”)

[“Kid, homework isn’t a punishment. Life is short and learning is hard, so studying a little every day is for your own sake!” “In that case, if I don’t want to be learned, I can take a break?” “Don’t be fresh!”]