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Published by Manz, Vienna: 1986. Reproduced with their permission.

excerpt from

Uniform Sales Law - The UN-Convention on Contracts for the International Sale of Goods

Univ. Prof. Dr. Peter Schlechtriem [*]


C. Usages (Article 9)

Article 9(1) binds the parties to any usages to which they have agreed - either through their negotiations or by their course of dealing.[116b] This provision corresponds to ULIS Article 9(1) and confirms the parties' autonomy over the contents and formation of the contract. Of course, Article 4(a) still mandates respect for domestic laws that prohibit certain trade practices and void contracts concluded by such means. The so-called "normative" usages were extremely controversial. According to the German understanding, their validity is not based on the parties' agreement. The Convention adopts in Article 9(2), as in Article [page 40] 8(2) of the 1978 Draft Convention, the legal construction - which in certain cases may be accurate - that a usage is binding due to an implied silent agreement between the parties.[117] A usage is binding only where the parties knew or ought to have known of the particular usage. This provision probably produces the same results as the restrictions of ULIS Article 9(2) sentence 1 and ULF Article 13(1).[118]

The last part of Article 9(2) restricts the kind of usages which must be observed.[119] The formulation reflects the concerns that some delegations had regarding respect for trade usages.[120] The requirement that the usage must be widely known in international trade, if taken literally, would mean that trade usages would generally have little effect. But Article 9(2) specifies that usages are defined with reference to the particular branch of the trade involved and to the parties who form contracts like the one concerned in a particular case. This is especially important when defining "international," "widely known" and "regularly observed." This means respect for usages existing, for example, in the international grain trade and followed by the parties who buy and sell grain on the international market. It is irrelevant, on the other hand, whether the practice is known "internationally" outside grain-trade circles.

Basically, Article 9(2) is an "internationalized" version of the requirements in German law for development and recognition of a binding trade usage: actual use, the consent of those who deal in the relevant trade transactions, and a certain duration,[121] factors which are basic in other legal systems as well.[122] In comparison to ULIS Article 9(2) and ULF Article 13(1), however, Article 9(2) restricts the recognition of national, regional or local usages which were developed for domestic sales and are not regularly followed in international transactions. These [page 41] usages cannot be "internationalized" simply because a foreign party knew or should have known of the custom.[123] The Chinese proposal that only reasonable usages should be recognized,[124] which would have given domestic courts control over the contents of usages, was rejected;[125] however, domestic prohibitions of certain trade customs which have the effect of voiding the contract remain operative (Article 4(a)).

There was no support for the view expressed by the Czechoslovakian delegation that the rules of the Convention should have priority over trade usages. The fact that the legal relevance of usages is based on a tacit agreement made it easier to accept them as a consequence of the priority of party autonomy over the Convention's rules.[126] The Conference also rejected a Pakistani proposal that would have permitted one party's conduct to prevent a finding that the parties had agreed on a usage.[127] Accordingly, it can be assumed that a party can show that a usage does not apply only by proving that it rejected it.

According to the version formulated in Vienna, usages explicitly apply to the formation of the contract as well. Nevertheless, it remains unclear whether usages such as those developed in Germany concerning the "commercial letter of confirmation" will be respected. The United States delegation, in presenting arguments for its proposal to include as usages those concerning contract formation, mentioned cases in which silence operates as the acceptance of an offer.[128] Therefore, it seems possible, in principle, to recognize usages in which silence means approval, if they meet the requirements of Article 9(2).

However, the requirements for according legal consequence to the silence of a party receiving a letter of confirmation would be considerably narrower in international commercial transactions than for internal dealings. But even according to the wording of ULFIS Article 13(1), which itself permits the "internationalization" of German usages, due consideration had to be given to whether the other side was informed or could have been informed. The substantive requirements for an effective letter of confirmation, i.e., that silence may be regarded as consent, would not be met if the foreign party were uninformed.[129] The wording of Article 9(2), which corresponds to the rules recognized in Germany, permits a letter of confirmation to be effective only if it is used in that particular branch of business in several countries and if the practice is acknowledged to have the legal consequence that silence means consent.

Finally, there was no support for the Egyptian proposal to include in the Convention ULIS Article 9(3).[130] As a result, guidelines for a uniform interpretation [page 42] of Incoterms, for example, are lacking. On the other hand, in practice, Article 8(2) should, in general, be able to fulfill the function of ULIS Article 9(3) in these cases.[130a][page 43]



* The author of this book participated at the Conference as a member of the delegation from the Federal Republic of Germany. The views expressed here are personal to the author and do not necessarily represent the position of the F.R.G. or its delegation.


116b. Eörsi argues that, under Article 9(1), usages must be made explicitly applicable, while Article 9(2) allows an implicit agreement. Eörsi, General Principles at 9; see also Réczei, Fields of Application at 179-182; Bydlinski at 75; contra Bonell, 107 östJBL 385 (1985).

117. In contrast to normative grounds, contractual intent as the ground for the applicability of usages means that capacity to contract and defects of will can gain importance as questions of "validity" under Article 4(a). As to the Hague Convention, see Dölle (Schlechtriem) ULF Article 13 § 4. The contrary view of Bonell, östJBL 385, seems to be desirable, but can hardly be based on the history of art. 9 and will lead to diverging interpretations; see Bergsten, Basic Concepts of the UN Convention on the International Sale of Goods, 20, 21. See also Bydlinski at 76 for an important advantage of the contractual approach: There can be no doubt that usages prevail over the rules of the Convention.

118. For ULF Article 13(1), see Dölle (Schlechtriem) Article 13 §§ 7 et seq. at 11.

119. Cf. Réczei, Rules of Application at 82 et seq.; Eörsi, General Provisions at 2-23.

120. See Enderlein at 33 ("Unification of law must not sanction customs developed by capitalistic monopolies vis-ŕ-vis weaker parties, especially in developing countries. On the other hand, unification of sales law can take into account, as its cornerstone, such international usages and customs which can rightly be considered as democratic and equitable"). But see Maskow § 2.4 at 58 ("quite happy with the present formula . . . while other socialist countries may feel some hesitations"). See also A/Conf. 97/C.1/SR.6 (= O.R. 263) at 9 § 71 (position of the Yugoslavian delegate); A/Conf. 97/C.1/SR.7 (= O.R. 266) at 4 § 19 (remark by the Soviet delegate that the version represents a compromise on one of the most controversial issues debated in UNCITRAL). Eörsi is very informative on the reasons behind the Socialist countries' position on usages. See Eörsi, General Provisions, Appendix. As for the reservations of the developing countries, see Date-Bah at 46-47.

121. See Judgment of Oct. 27, 1951, BGH, 1952 NJW 257.

122. Cf. Dölle (Junge) Article 9 § 3; Sonnenberger, Verkehrssitten im Schuldvertrag 61 et seq. (1970).

123. But, as to the Hague Conventions, see Dölle (Schlechtriem) ULF Article 13 § 7 at 11-12.

124. A/Conf. 97/C.1/L.24 (= O.R. 89).

125. See also A/Conf. 97/C.1/SR.6 at 8-9 (= O.R. at 262 et seq.) (discussion).

126. See A/Conf. 97/C.1/SR.6 at 10-11 (= O.R. 263).

127. See A/Conf. 97/C.1/L.64 (= O.R. 89) (motion); A/Conf. 97/C.1/.SR.7 at 4-5 (= O.R. 266 et seq.) (discussion). Acceptance of the proposal would have meant that a party could have invalidated part of a usage by neglecting to follow the behavior prescribed by it.

128. Cf. A/Conf. 97/C.1/SR.6 at 11 § 88 (= O.R. 264).

129. Cf. O. Sandrock, Handbuch der Internationalen Vertragsgestaltung 263 et seq. (1980); Dölle (Schlechtriem) ULF Article 13 § 10.

130. Cf. A/Conf. 97/C.1/SR.7 at 5-6 (= O.R. 267).

130a. See Honnold, Commentary § 120 (suggesting that contract provisions could be construed in light of the applicable usage).


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