Dàyǎn suǒyǐn 大衍索隱
Index-Searching of the Great Expansion by 丁易東 (Dīng Yìdōng, late Sòng / early Yuán Sòng-loyalist, 宋, zhuàn 撰)
About the work
Dīng Yìdōng’s 3-juan systematic explication of the dàyǎn zhī shù 大衍之數 (great-expansion number = 50) of the Yìjīng’s Xìcí — the foundational Confucian numerological-divinatory parameter. Dīng Yìdōng was a late-Sòng jìnshì, Cháofèng dàfū Tàifǔsì zhǔbù (Court Gentleman / Imperial Stables Records-Keeper), and Zhěnqián cōngbīngsuǒ biānxiūguān (Privy Council Editor); refused service under the Yuán; built a private academy and taught students; later served as Yuányáng shūyuàn shāncháng (Director of the Yuányáng Academy).
Structure (per the 提要):
- Yuányǎn 原衍 (Original-Expansion) — 36 figures expounding the meaning of dàyǎn zhī shù wǔshí, qí yòng sìshíjiǔ “the great-expansion number is 50, [we] use 49”
- Yìyǎn 翼衍 (Wing-Expansion) — 29 figures elaborating the Hétú and related diagrams
- Jīyǎn 稽衍 (Examination-Expansion) — comparative collation of 57 different schools’ dàyǎn interpretations from the Yì wěi Qiánzáo dù onwards, with Dīng Yìdōng’s critical assessment
The work was nearly lost: alternative recensions had dropped the Jīyǎn section entirely; the Sìkù editors recovered it from the Yǒnglè dàdiǎn and reorganized the material per the original table-of-contents. The work is one of the principal late-Sòng Yìjīng-numerological compendia.
For the broader Yìjīng-numerological tradition, see KR3g0001, KR3g0005, KR3g0007, KR3g0013, KR3g0015.
Tiyao
[Full text in source file. Dated Qiánlóng 46 (1781), ninth month.]