Guide to the use of this commentary
The Secretariat Commentary is on the 1978 Draft of the CISG, not the Official Text, which re-numbered most of the articles of the 1978 Draft. The Secretariat Commentary on article 19 of the 1978 Draft is quoted below with the article references contained in this commentary conformed to the numerical sequence of the Official Text, e.g., article 19 [draft counterpart of CISG article 21].
To the extent it is relevant to the Official Text, the
Secretariat Commentary on the 1978 Draft is perhaps the
most authoritative source one can cite. It is the
closest counterpart to an Official Commentary on the
CISG. A match-up of this article of the 1978 Draft
with the version adopted for the Official Text is
necessary to document the relevancy of the Secretariat
Commentary on this article. See the match-up for this article for a validation of citations to this
Secretariat Commentary. This match-up indicates that article 19 of the 1978 Draft
and CISG article 21 are substantively identical.
Text of Secretariat Commentary on article 19 of the 1978 Draft
[draft counterpart of CISG article 21] [Late acceptance]
PRIOR UNIFORM LAW
ULF, article 9.
1. Article 19 [draft counterpart of CISG article 21] deals with acceptances that arrive after the expiration of the time for acceptance.
Power of offeror to consider acceptance as having arrived in due time, paragraph (1)
2. If the acceptance is late, the offer lapses and no contract is concluded by the arrival of the acceptance. However, article 19(1) [draft counterpart of CISG article 21(1)] provides that the late acceptance becomes an effective acceptance if the offeror without delay informs the acceptor orally or by the dispatch of a notice that he considers the acceptance to be effective.
3. Article 19(1) [draft counterpart of CISG article 21(1)] differs slightly from the theory found in many countries that a late acceptance functions as a counter-offer. Under this paragraph, as under the theory of counter-offer, a contract is concluded only if the original offeror informs the original offeree of his intention to be bound by the late acceptance. However, under this paragraph it is the late acceptance which becomes the effective acceptance as of the moment of its receipt, even though it requires a subsequent notice to validate it. Under the counter-offer theory it is the notice by the original offeror of this intention which becomes the acceptance and this acceptance is effective only upon its arrival.
Acceptances which are late because of a delay in transmission, paragraph (2)
4. A different rule prevails if the letter or document which contains the late acceptance shows that it was sent in such circumstances that if its transmission had been normal, it would have been communicated in due time. In such case the late acceptance is considered to have arrived in due time, and the contract is concluded as of the moment the acceptance reaches the offeror, unless the offeror without delay notifies the offeree that he considers the offer as having lapsed.
5. Therefore, if the letter or document which contains the late acceptance shows that it was sent in such circumstances that if its transmission had been normal, it would have reached the offeror in due time, the offeror must notify, without delay, the offeree to prevent a contract from being concluded. If the letter or document does not show such proper dispatch and the offeror wishes the contract to be concluded, he must notify, without delay, the offeree that he considers the acceptance to be effective pursuant to article 19(1) [draft counterpart of CISG article 21(1)] (OFFICIAL RECORDS, p. 25).