Until the concept of "positive infringement of creditor’s right" was claimed,repudiation was accepted as a form of positive infringement of creditor’s right by theory and practice of judicial for the first time.

Generally speaking, anticipatory breach of contract of Anglo-American Law is a good way to treat repudiation or frustration of contract before the deadline for performance.

Repudiation had not been included in the system of non-performance since Roman law of civil legal system until the concept of“positive infringement of creditor’s right”was claimed, repudiation was accept as a form of povitive infringement of creditor’s right by theory and practice of judicial for the first time.

The system of refusal to fulfill in the Continental system corresponds to the prospective contract breakage system in the British and US system.

In the Continental law, refusal to fulfill and right of unstable pleadings have the similar functions.

Request act and refusal act were chosenas the teaching targets.

The refusal act against request in Japanese letters largely shows a discourse structure of "confirming communica- tive presupposition / confirming relationship between both sides + core refusal words + secondary refusal words".