…by beating it in a game of chess
(Noren ni ude-oshi; “arm-wrestling a curtain”)
A deed with no resistance, therefore requiring no real effort, and therefore giving no thrill or satisfaction for the accomplishment. A waste of effort. Alternately, being completely ineffective. Like arm-wrestling one of the hanging curtains that adorn many Japanese shop-fronts (especially restaurants) – they need to be pushed aside to enter, but are typically made of light cloth and lack both the power and will to respond meaningfully.
This is two nouns connected by the directional particle に (ni). The first noun – the one the implicit action is being directed into – is 暖簾 (noren), a traditional hanging curtain that hangs just low enough that most people can’t simply walk under it. The second noun is 腕押し (udeoshi), literally “arm-pushing.”
In contemporary Japanese, the term udeoshi seems to refer to a shove used in sumo wrestling. My sources note that there is some debate over whether this kotowaza refers to a simple push or to arm-wrestling, but the latter interpretation seems overall to be favored even if the word udeoshi itself is more ambiguous. Apparently the arm-wrestling reading is supported by usage in texts such as the 義経記 (“The Chronicles of Yoshitsune”) and the first ever European dictionary of Japanese, the 1603 日葡辞書 (Nippo Jisho).
(“Okotteru nisaiji wo settoku suru no nante, noren ni udeoshi da. Ochitsuku no wo matsu shika nai na.”)
[“There’s no point to trying to convince an angry two-year-old. All you can do is wait for them to calm down.”]