虎とらの巻まき

expression, noun

book of secrets; inside information; trade secrets

Refers to a document or knowledge containing confidential tips, tricks, or know-how, often in business, crafts, or specialized fields. Idiomatic, derived from the legendary Chinese military text.

• 彼かれはその業ぎょう界かいの虎とらの巻まきを持もっていると言いわれている。

  He is said to have the inside secrets of that industry.

expression, noun

study guide; crib; answer key

Commonly used for supplementary materials that reveal answers, solutions, or effective study methods for textbooks or exams. Often has a slightly informal, 'cheat sheet' connotation.

• 試し験けん前まえに友とも達だちから虎とらの巻まきを借かりた。

  I borrowed a study guide from a friend before the exam.

• この参さん考こう書しょはまるで虎とらの巻まきだ。

  This reference book is practically a crib.