X53 Classification Numbers - General Information

Field definition and scope:

The indicators, subfield codes, and input conventions for the classification number fields listed below follow similar patterns.

153 Classification Number (NR)

453 Invalid Number Tracing (R)

553 Valid Number Tracing (R)

See the specific field for its repeatability.

Guidelines for applying content designators:

The content designators identify the subelements occurring in classification numbers that are constructed according to the classification scheme that is identified in field 084 (Classification Scheme and Edition). These fields may contain a single classification number (008/07, Type of number, code a) or a span of classification numbers (008/07, code b or c) from a schedule (008/06, Kind of record, code a) or from a table (008/06, code b) and its associated caption (subfield $j) and caption hierarchy (subfield $h and $k). The subject context of the classification number is indicated by the preceding hierarchy captions contained in repeatable subfields $h and $k. (Fields 153, 453, and 553 must contain at least one subfield $a and one subfield $j.)

For indicator and subfield code definitions and examples, and designator repeatability, see table below. An asterisk ( * ) in the column indicates that the requirement varies. See table in the specific field.:

Position	Description	Repeatability
Field X53	Classification Number	*
Indicator:
First
153	Undefined; contains a blank

453, 553	Source of classification number
0	Schedule
1	Table

Second	Undefined; contains a blank

Subfield code:
	Name portion
$a	Classification number - single number or beginning number of span	R
$c	Classification number - ending number of span	R
$e	Classification number hierarchy - single number or beginning number of span [153]	R
$f	Classification number hierarchy - ending number of span [153]	R
$z	Table identification	R

	Caption portion
$h	Caption hierarchy	R
$j	Caption	NR
$k	Summary number span caption hierarchy	R
$y	Table sequence number for internal subarrangement or add table	R

	Tracing and control subfields
$i	Reference instruction phrase [453, 553]	NR
$t	Topic [453, 553]	NR
$w	Control subfield [453, 553]	NR
$6	Linkage	NR
$8	Field link and sequence number	R

Input conventions:

Order of subfields

Invalid classification numbers

Number spans

Display of classification numbers and captions

Scheme-specific conventions:

Library of Congress Classification

Dewey Decimal Classification

Content designator history:

Subfield $e - Classification number hierarchy - single number or beginning number of span [new, 2008]

Subfield $f - Classification number hierarchy - ending number of span [new, 2008]

Subfield $y - Table sequence number for internal subarrangement or add table [new, 2008]

Subfield $z - Table identification [redefined, 2008]: Subfield $z was redefined as repeatable.