What do you do when the work environment at the stable drives away all the competent grooms?
(Keru uma mo norite shidai; “A kicking horse depends on the rider”)
Even a violent, difficult-to-handle person can be talked to and dealt with successfully by the right person, or using the right methods. In theory at least, there’s a way to approach and defuse almost any situation no matter what kind of person you’re dealing with. The analogy is of a horse who tends to kick, asserting that even they can be ridden by someone who gives them appropriate training.
The primary noun is 馬 (uma), “horse,” here preceded and modified by the verb 蹴る (keru), “to kick,” in prenominal form. The horse is marked by the particle も (mo), “also” or “even” – its usage here implies that the example of the horse is perhaps a bit extreme or unusual, which quality in turn demonstrates the universality of the following rule.
This rule is expressed by the noun 手 (te), literally “hand” but in this case meaning “person who does a thing.” (See also 相手 aite, 選手 senshu, 歌手 kashu etc.) The “hand” is preceded and modified by the verb 乗る (noru) in conjunctive form, allowing it to function as a noun and effectively, as far as I can tell, making 乗り手 into a compound noun. This feels a bit odd, but is a common structure in expressing “a person who does a thing” in a general sense, where e.g. 乗る人 (noru hito) using the prenominal form, expresses “the specific person who is riding.”
Any further particles are elided, and we are left with nominal suffix 次第 (shidai), “depending on,” to tie the horse and rider together (grammatically).
Some variants will talk about 癖ある馬 (kuse aru uma), horses with (bad) habits, or even 人食い馬 (hitogui uma), horses that “eat” (bite) humans!
(Keru uma mo norite shidai to nando mo keikai sareteru kedo, Uemura-san wa mada ichido mo juudou no shiai de maketa koto ga nai kara, donna basho de mo muteki da to iwan bakari no taido wo toru hito deshita.)
[He had been warned time and time again that there’s a way to deal with any opponent. But since Uemura had yet to lose a single judo match, no matter where he went, he struck an attitude as if he had nothing to fear from anyone.]