Contract validity and the CISG

The article discusses the standards that determine the validity of contracts that are governed by the United Nations Convention on Contracts for the International Sale of Goods of 1980 (CISG). While Article 4(a) of the—CISG � the so-called ‘validity exception’—generally excludes the validity of the contract from the Convention's material scope, it does so incompletely by adding a ‘except as otherwise expressly provided in this Convention’ caveat. Against this background, the article sets out to develop a novel validity definition. According to this definition, provisions concerned with the ‘validity of the contract’ in the sense of Article 4(a) of the CISG are legal limits to party autonomy. The article continues by applying this definition to various potential validity issues as discussed in case law and legal writings. In doing so, it distinguishes between validity issues clearly not covered by the CISG (as legal limits on what to sell, legal limits on who to sell to or to purchase from, and legal limits on how to sell) and validity issues clearly covered by the CISG, as the formal validity of contracts, the validity of open-price contracts and the effect of an initial objective impossibility of the agreed performance on the contract. Finally, the article discusses a more complicated group of borderline issues that may or may not be governed by the Sales Convention, as mistakes or misrepresentations by a contracting party, the effect of contract clauses limiting a party's rights under the contract, surprising contract clauses and the effect of legal prohibitions of interest