The sandpiper and the clam fight one another
Refers to when a third party benefits from the struggle of others
Negative
今年夏天，电器业者鹬蚌相争，降价促销，消费者成了最大的赢家 | Jīnnián xiàtiān, diànqì yèzhě yùbàngxiāngzhēng, jiàngjià cùxiāo, xiāofèizhě chéng le zuì dà de yíngjiā
This summer, the electronics vendors fought amongst each other have the lowest prices, and the consumers became the ones who benefited the most
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由于他们两人不肯合作，鹬蚌相争，结果把大好机会白白地送给对手 | Yóuyú tāmen liǎng rén bù kěn hézuò, yù bàng xiāng zhēng, jiéguǒ bǎ dàhǎo jīhuì báibái dì sòng gěi duìshǒu
Because the two of you were unwilling to work together and kept fighting each other, you needlessly gave your opponent a great opportunity
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None
鹬蚌相争，渔翁得利 (yù bàng xiāng zhēng, yú wēng dé lì)
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《战国策》(Zhàn Gúo Cè, Strategies of the Warring States), a work which chronicled the Warring States Period (475 - 220 BC)
On a warm and pleasant day, a freshwater mussel hopped onto the banks of its river, opened up its shell, and started soaking up some sun. It wasn't long before a passing sand piper caught sight of the mussel, and it immediately tried to take a bite.
The mussel responded by clamping its shell firmly shut around the sandpiper's beak. The sandpiper tried to break away, but found itself utterly unable to move. Similarly, the mussel quickly found that it couldn't break away from its attacker to jump back into the river. At this, the two creatures started arguing ferociously.
The sandpiper spat in a muffled voice, "If it doesn't rain in a day or two, you won't be able to return to the river, and you'll die here."
The mussel retorted around the sandpiper's beak, "If I don't let you go and you can't get out within a few days, you'll starve to death!"
They continued arguing furiously, with neither gaining the upper hand. At this point, a fisherman arrived at the river and saw the mussel and sandpiper locked together. Immediately, he scooped them up, and, the day's work already done, he returned home for a nice meal.