Small Trust Builds Large Trust / 小信诚则大信立

Small trust builds large trust / 小信诚则大信立 is the trust principle emphasized in 《资治通鉴·周纪》05｜光彩夺目的魏文侯（1）. The episode uses 魏文侯’s rainy hunting appointment to argue that political credibility is built from minor promises as well as formal declarations.

The source extends the claim through 司马光’s criticism of a Song court reward case: if the state promises office to whoever captures a major robber, then replacing that promise with money damages public credibility even if the immediate case looks administratively small. The source also keeps a practical tension visible: in real statecraft, aligning small promises with large interests is harder than the slogan suggests, and a Legalist ruler-technique frame may treat high-stakes affairs more conditionally.

《资治通鉴·周纪》13丨 公孙鞅苛刻变法惹杀身（1） adds a sharper Qin variant through 徙木立信. 公孙鞅 / 商鞅 proves that the state will pay a strange but public reward before issuing the reform law. The episode treats this as credibility built for coercive execution, not only as ruler virtue.

Key Claims

• Minor promises function as public tests of whether a ruler’s word means anything.
• State credibility is damaged when a government changes promised terms after people rely on them.
• Trust is not only personal virtue; it becomes a condition for stable rule.
• The concept links Confucian moral politics to Social Trust As State Capacity, but the episode keeps its claim source-scoped rather than generalizing it into a universal rule.
• In the Shang Yang case, a small kept promise prepares people to believe later rewards and punishments will also be enforced.

Connections

• 魏文侯 - ruler used for the hunting-appointment example.
• 司马光 and 《资治通鉴》 - interpretive frame.
• Confucian Ideal Governance / 儒家理想治理 - moral-political setting.
• Legalist Ruler Technique / 法家君术 - contrast around whether small and large trust always align.
• Renhe Political Power / 人和政治力量 and Symmetric Interstate Credibility / 对称外交信用 - adjacent source concepts.
• 徙木立信 / Moving the Log to Build Trust, Shang Yang Reforms / 商鞅变法, and Legalist Ruler Technique / 法家君术 - Qin reform credibility branch.
• Social Trust As State Capacity - broader wiki frame for trust as a governance asset.