(1) Where the parties are to perform simultaneously, either party may withhold performance until the other party tenders its performance.
(2) Where the parties are to perform consecutively, the party that is to perform later may withhold its performance until the first party has performed.
This Article must be read together with Article 6.1.4 (Order of performance). This Article is concerned with remedies and corresponds in effect to the civil law concept of exceptio non adimpleti contractus.
A agrees to sell B a thousand tons of white wheat, payment to be made by confirmed letter of credit opened on a bank from country X. A is not obliged to ship the goods unless and until B opens the letter of credit in conformity with its contractual obligations.
The text does not explicitly address the question which arises where one party performs in part but does not perform completely. In such a case the party entitled to receive performance may be entitled to withhold performance but only where in normal circumstances this is consonant with good faith and fair dealing (see Article 1.7).