A new service called "SQmatch" is now available in DDBJ WWW site. This service is matching a regular expression against sequences in Database. It is effective for the short sequences and such as those including "N" (undetermined).The URL is http://ftp2.ddbj.nig.ac.jp:8080/sqmatch_en.html.This has a link from [Database Searches and Data Analyses] of DDBJ Home Page.