It is often felt and suggested that arbitrators can help in finding, and possibly creating, a commercial law being identical in all countries where a particular commerce is performed, in other words a lex mercatoria governing their particular commercial activities. This aim, of course, presupposes that these arbitrators know not only the law of their own country which they usually apply, at least in the majority of the cases handled, but also presupposes that they are acquainted with certain aspects of the law of other countries too. This acquaintance with principles of a foreign law can be promoted by lawyers who can describe to a Judge or an arbitrator how certain legal questions are answered by another national law. This can and should always be done in cases where similar or identical commercial transactions are effected in various countries and where an answer is not yet readily prepared by a written statute or by a precedent. In other words, comparison of law is needed because it is useful and, last but not least, because it is demanded by clients of lawyers and by users of the arbitration process.

In fact, it is practised and one knows judgments containing hints of a foreign law or even where the decision is based wholly or partly on foreign law as expressed by a statute, or by a judgment, or explained by learned writers. One also knows arbitration awards which have been reasoned in this manner, and one is aware of numerous awards rendered on this basis, e.g. in Paris, Gdynia or in Hamburg.

Such an only partially unified lex mercatoria can also be created, or helped to be created, by arbitrators working in more than one venue and thus becoming acquainted with different, and often differing, national (substantive) laws.

If one tries to compare various national laws one is astonished to see how many different answers are given internationally to questions where one would expect an identical answer in view of the fact that merchants are doing, at different places, business of the same kind and in the same manner believing, and being convinced, that they are acting on a common factual and consequently also a common legal basis. But, regrettably, very often this is not so. And, as may be added, Judges and arbitrators should be aware of this situation more than ever before.

Examples are numerous and some of them will be mentioned.

In England, the Court of Appeal recently was called upon to decide as to whether a creditor who has received belated payment is entitled to claim just interest, i.e. interest