一言莫衍 / Yi Yan Moyan

Overview

一言莫衍 / Yi Yan Moyan enters the wiki through Hanji 510 as a 匈奴 envoy sent to 西汉 who unexpectedly asks to defect before returning north.

Current Profile

The source uses Yi Yan Moyan as the test case for a Chengdi-era diplomatic judgment. His request looks attractive under older Han practice, when accepting Xiongnu defectors could weaken a hostile frontier power. 谷永 and 杜钦 argue that the context has changed because the chanyu is now formally submissive; accepting the envoy could damage trust with the chanyu or reward a deliberate test.

Chengdi accepts the refusal logic. After questioning, Yi Yan Moyan says he had been mad when he asked to defect, and Han sends him back to Xiongnu. The episode says his office is preserved after return, but the chanyu never lets him meet Han envoys again.

Key Characteristics

• Xiongnu envoy to Western Han during Chengdi’s Heping 2 context.
• Requests defection before returning north, threatening suicide if Han refuses.
• Becomes a diplomatic credibility test because his ruler is treated as a submitted chanyu rather than an open enemy.
• Later retracts the request by claiming madness after Han questions him.

Evidence

• Defection request: Hanji 510 says Yi Yan Moyan asks to surrender to Han before returning to Xiongnu and threatens suicide if refused.
• Refusal logic: Hanji 510 says Gu Yong and Du Qin warn that accepting him could alienate the submitted chanyu or fall into a trap.
• Return outcome: Hanji 510 says Han sends him back after he claims madness, and that his office remains but contact with Han envoys is barred.

Qualifications

This page is bounded to Hanji 510. It does not reconstruct Yi Yan Moyan’s full office, Xiongnu factional context, standard-history name form, or true motive for the defection request.

What Changed

• Created the page from Hanji 510’s Xiongnu defection episode.

Relationships

• 匈奴 - polity Yi Yan Moyan represents as envoy.
• 汉成帝 - Han ruler who refuses the defection request.
• 谷永 - official who helps argue against accepting the defection.
• 杜钦 - official who helps argue against accepting the defection.
• 边疆册封信用权衡 - concept illustrated by the risk of trading one defector for a larger frontier relationship.