Introducing counterparts in your language for other posts might be fun for anyone.
Wer rastet, der rostet I feel it is very Germany for it is said that Germany is diligence and stoic. We have these below. I feel ambiguous moral and luck is needed to rule oneself is Japanese-like.
善は急げ/As for goodness, be hurry up. ( Zenha isoge )
思い立ったが吉日/When you decide is your lucky day. ( Omoi tattaga kichijitsu )
Good things come We have its counterpart "果報は寝て待て/As for a fruition report, sleep and wait it" (kahou ha nete mate ) . It origins from Buddhism and the original meaning was "As for a fruition and payback of your doing on your previous life, sleep and wait it" and it contained both good and bad fortunes. But because of the character 報 has both meaning of payback and report, it means only a good thing nowadays.
Chi di spada ferisce, di spada perisce For this phrase is quoted in many samurai manga, I thought it was a phrase of a renowned samurai. "身から出た錆/Body-born rust" ( Mi kara deta sabi ) is our counterpart for it. It originally means "Blade-born rust" for 身 meant "body of sword" but most Japanese think it a human body now.
Shooting Sparrows With Cannons We have many proverbs in a style of "casting pearls before swine" which means "no gain from a big investment" but lack of famous one that means less gain from much effort. I searched for it and found there's "大根を正宗で切る/To cut a daikon with Masamune" ( Daikon wo Masamune de kiru ) but very infamous. "獅子は兎を狩るにも全力を尽くす/A lion takes its best efforts to hunt even if the prey is a rabbit" ( Shishi ha usagi wo karu nimo zenryoku wo tsukusu ) which has an opposite meaning is very famous in Japan.