MARBI discussion paper 2007-06 provides details
<http://www.loc.gov/marc/marbi/2007/2007-06.html>

Basically, it's to support German and Austrian conversion to MARC21 (although some in the conser community have pointed out that since conser is no longer requiring formatted 362, that the 363 could be the place for universal pattern data.

Steve Shadle/Serials Access Librarian  *****  shadle@u.washington.edu
University of Washington Libraries      ***     Phone: (206) 685-3983
Seattle, WA 98195-2900                   *        Fax: (206) 543-0854

On Tue, 22 Apr 2008, Corrice, Julia A. wrote:

> In the latest update we received for MARC Format for Bibliographic Data,
> a new field (363) for the normalized date in the 362 was added. Is
> anyone going to be using this field? I'm wonding what potential
> usefulness it might have.
>
> http://www.loc.gov/marc/bibliographic/bd363.html
>
>
> Julia Corrice
>
>
> Serials
> Rakow Library
> Corning Museum of Glass
> 5 Museum Way
> Corning, NY 14830
> (607) 974-8406
> (607)974-8677 fax
> www.cmog.org
>
>