黑白分明 clear-cut
Explanation
比喻事情的是非、好坏界限清楚，很容易分辨。
It is used to describe something whose right and wrong, good and bad boundaries are clear and easy to distinguish.
Origin Story
话说隋唐时期，名将秦琼和尉迟恭两人武艺超群，被人们誉为“双雄”。一次，两人比武，秦琼使一杆亮银枪，枪法如闪电般迅猛，尉迟恭使一条丈八蛇矛，招式变化莫测。两人大战数十回合，不分胜负。这时，太阳渐渐西下，天色暗了下来。这时，只见秦琼的银枪上银光闪闪，而尉迟恭的蛇矛上却沾满了泥土，显得格外暗淡。只见秦琼一枪刺向尉迟恭，尉迟恭来不及躲闪，被刺中肩膀，顿时鲜血直流。尉迟恭大怒，奋力反击，但终究不敌秦琼，败下阵来。这场比武，胜负黑白分明。
During the Sui and Tang dynasties, the famous generals Qin Qiong and Yuchi Gong were known for their extraordinary martial arts skills and were praised as "two heroes". Once, the two of them competed in martial arts. Qin Qiong used a bright silver spear, and his spear skills were as swift as lightning. Yuchi Gong used an eighteen-foot snake halberd, and his moves were unpredictable. After dozens of rounds of fierce fighting, the two were still evenly matched. At this time, the sun gradually set, and the sky darkened. At this time, Qin Qiong's silver spear shone brightly, while Yuchi Gong's snake halberd was covered in mud and looked exceptionally dim. Qin Qiong stabbed at Yuchi Gong with his spear. Yuchi Gong had no time to dodge and was hit in the shoulder; blood flowed immediately. Yuchi Gong was furious and fought back with all his might, but he was eventually no match for Qin Qiong and lost the fight. The outcome of this competition was clear.
Usage
常用来形容是非、好坏、善恶界限分明，容易分辨。
It is often used to describe that the boundary between right and wrong, good and bad, is clear and easy to distinguish.
Examples
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这场比赛，胜负黑白分明。
zhe chang bisai shengfu heibaifenming
The result of this match is clear.
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他的书法，黑白分明，很有力道。
ta de shushu heibaifenming hen you lidao
His calligraphy is clear and powerful.
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是非曲直，黑白分明，不容抵赖。
shifei quzhi heibaifenming, bulong dila
Right and wrong are clear and undeniable.