秦国 / Qin State
秦国 / Qin State appears in 《资治通鉴·周纪》06丨魏文侯选谁当宰相呢（2） through 秦嬴, whom the episode explains as a Qin princess by name pattern rather than as someone surnamed Qin. The source also uses Qin-Jin intermarriage to explain the idiom “秦晋之好.”
This page is source-scoped and mainly supports the episode’s kinship and assassination-attribution example. It connects backward to 晋国 and forward to the wiki’s existing Qin-related material through 秦始皇.
《资治通鉴·周纪》07丨两起刺杀（1） adds an early Warring States Qin chronology branch: Qin attacks 魏国 in 401 BCE, then 秦简公 dies and his son 秦惠公 succeeds him in 400 BCE.