The increase in international trade is clearly reflected by litigation and arbitration. Despite the importance of international commercial transaction, until very recently little was known about how the law interacts with actual practice. The CISG obviously plays an important role, but we are concerned with using choice of law to resolve issue that the CISG leaves unresolved. The case law UPICC is now accessible by means of UNILEX, the database on international case law that focus on CISG cases. The courts and arbitration tribunals throughout the world are developing a growing body of international case law on issues not resolved by the CISG, though arising from transactions to which the CISG applies. The application of the CISG is obligatory due to its nature as hard law an international convention. However, UPICC are only restatements and more flexibility, comprehensive instrument than CISG. This article offers to promote the UPICC application from their present status as a mere soft law instrument through analysing UNILEX cases.