郑国 / Zheng State
郑国 / Zheng State enters this branch through 《资治通鉴·周纪》07丨两起刺杀（1）, where 芮淇讲透资治通鉴 uses Zheng to explain both small-state diplomacy and internal political violence. The source says Zheng had once grown strong under Zheng Zhuang Gong, but its location between 晋国 and 楚国 left it exposed whichever great-power patron it chose.
In the episode, Zheng besieges 韩国’s Yangdi soon after 韩景侯 dies, then is itself besieged by 楚国 at Xinzheng after appearing to side with Jin. Internally, the killing of prime minister 子阳 and the later installation of 郑康公 by Ziyang’s faction make Zheng the source’s main example of the shift from rule-bound aristocratic politics to harsher Warring States power struggle.
《资治通鉴·周纪》07丨两起刺杀（2） completes that Zheng thread: 子阳’s remaining faction kills 郑繻公 and installs 郑康公. The same source later treats 负黍’s return from Zheng to Han as evidence that Zheng’s territorial control is weakening.
《资治通鉴·周纪》08丨一代名将吴起惨死（3） adds another pressure point before Zheng’s final absorption: 韩国 attacks Zheng and takes Yangcheng in 385 BCE. The episode places the notice inside Han’s multi-generation drive against Zheng rather than treating it as a complete explanation on its own.
《资治通鉴·周纪》10丨 以家族单位 有蚂蚁吃大象的精神（1） closes this branch from the other side. 韩国 destroys Zheng in 375 BCE and moves its capital to Xinzheng; the episode reads this as the endpoint of several Han generations pressing toward Zheng through war and capital relocation.
《资治通鉴·周纪》75-1丨“穷奢极侈”的祖师爷管仲 adds a retrospective Spring-Autumn Zheng branch through 子产. The episode presents Zi Chan’s river-crossing kindness as humane but politically insufficient, then uses his early warning after Zheng’s attack on Cai to show the small-state danger of military victory that ignores 楚国 and 晋国 pressure.
Connections
- Small-State Buffer Diplomacy / 小国夹缝外交 - main geopolitical frame.
- Spring-Autumn to Warring States Political Violence / 春秋战国政治暴力转型 - internal violence frame.
- 子阳, 郑繻公, and 郑康公 - Zheng factional-assassination branch.
- 韩国, 晋国, and 楚国 - pressure field around Zheng.
- Yangcheng and Generational Family Strategy / 家族代际战略 - Zhouji 08 part 3 Han pressure before final absorption.
- 负黍 and Territorial Control Churn / 城池反复易手 - territorial-control branch.
- Generational Family Strategy / 家族代际战略, Strategic Capital Relocation / 战略性迁都, 韩康子, 韩武子, and 韩哀侯 - Zhouji 10 absorption by Han.
- 子产, 孟子 / Mencius, Good Intentions Political Limits, and Small-State Buffer Diplomacy / 小国夹缝外交 - Zhouji 75-1 governance and interstate-judgment extension.