船は帆で持つ帆は船で持つ
(Fune wa ho de motsu ho wa fune de motsu;
“A ship works because of its sail; a sail works because of its ship”)

Definition:

A ship is useful because it has a sail; a sail is useful because it’s on a ship. By analogy, people can only achieve things and do good in the world when they help and support each other. Different people have different tasks and functions, and these need to be combined for work to be done effectively.

Breakdown:

This set of parallel verb phrases begins with the noun 船 (fune), “ship,” “boat,” marked as the topic of discussion by the particle は (wa). The comment on this topic begins with the noun 帆 (ho), “sail,” marked as the means by which an action is performed by the particle で (de). In this case, the “action” in question is the verb 持つ (motsu), in conclusive form. We may need to be a bit careful about its meaning, though. Usually translated as “have,” in this case 持つ can be thought of as standing in for compound verb 受け持つ (ukemotsu), “to take on [a task],” “to do a job.”

The second half of the phrase is identical, but with 船 and 帆 switched. Some versions separate the two parts with a comma, but this is not necessary.

Notes:

The origins of this phrase are unclear, although one of my sources connects it with Buddhist ideas of “direct and indirect causes” (hetu and pratyaya, in Japanese 因縁 = in’nen).

Example sentence:

「街の文化協会は一年中、ほとんど喧嘩ばかりでつまらないものだけど、祭りの準備の時だけは皆が船は帆で持つ帆は船で持つことを突然思い出したかのように、お互い支え合って頑張る数週間が続く」

(“Machi no bunka kyoukai wa ichinenjuu, hotondo kenka bakari de tsumaranai mono da kedo, matsuri no junbi no toki dake wa mina ga fune wa ho de motsu ho wa fune motsu koto wo totsuzen omoidashita ka no you ni, otagai sasaeatte ganbaru suushuukan ga tsudzuku.”)

[“For almost the entire year, the city cultural association is a useless mess of bickering. It’s only for a few weeks during the runup to a festival that everyone suddenly starts supporting each other and working together, as if they’d suddenly remembered that each part of a whole only functions because of the other parts.”]