But I think that the include directive can also be used in regular jsp-pages.
You are correct - <%@ include file="..." %> can be used in any JSP or tag file. I use it (rarely) myself. Remember also it's a static (translation- and compile-time) import, while <jsp:include /> is dynamic (at request-time).
Charles Lyons (SCJP 1.4, April 2003; SCJP 5, Dec 2006; SCWCD 1.4b, April 2004)
Author of OCEJWCD Study Companion for Oracle Exam 1Z0-899 (ISBN 0955160340 / AmazonAmazon UK )