04ac3695_se_Notes___Amazon_Web_Services__Issue
[Description] ISBN numbers have increased to 13 digits. The existing EAN field can hold 13 digits. ItemSearch requests using the EAN field this way, however, return inaccurate results. [Impact] JP locale ItemSearch requests cannot use the EAN field for the ISBN number. The workaround is to use the "ISBN" for the IdType parameter in an ItemLookup request. In this case, the ItemId is the ISBN number of a book. The ISBN value works only with the Book search index. [Issue] 
The EAN field does not support ISBN-13 in the JP locale.
Release: Amazon E-Commerce Service on 2007-07-23 : Release Notes : Amazon Web Services