This is rule is number 25 in The Hundred Rules of War.
Tsukahara Bokuden was a samurai born in 1489. He fought in 37 battles and 19 duels. It’s said that he killed 212 in battle. Similar to Miyamoto Musashi, he wrote The Hundred Rules of War(also known as Lessons Left to Us by Bokuden) near his death, as Musashi wrote The Dokkodo his 21 rule for life.
Musashi was borne 95 years after Bokuden.
This is rule 44 in The Hundred Roles of War.
Functional Aesthetics are ideal in all situations.