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Bibliographic record leader elements

Find details about the elements of the bibliographic record leader.

The bibliographic record leader contains 24 Bytes of data. The leader is followed by record directory entries. There are no field terminators between the leader and the record directory or record directory entries.

In OCLC-MARC Records, any element, Value, field, subfield, etc., marked obsolete is no longer valid. Current records will not contain these invalid codes. However, records supplied from archives may contain obsolete MARC coding.

Ind = Indicator  |  SFC = Subfield code  |  R = Repeatable  |  NR = Nonrepeatable  |  Blank = Blank

Bytes 00-10

 Note: Mnemonics that appear on workforms and record displays follow the leader label.

Byte Value Definition

Record Length

  • 5-character number = length of the entire record
  • Right-justified with leading zeros
  • Minimum length = 124
  • Maximum length = 6,144
05   Record Status (Rec stat)
a Increase in encoding level
c Corrected or revised
n New
p Increase in encoding level from prepublication
06   Type of Record (Type)
a Language of material

Archival and manuscripts control

 Note: Value obsolete

c Printed music
d Manuscript music
e Cartographic material
f Manuscript cartographic material
g Projected medium
i Nonmusical sound recording
j Musical sound recording
k 2-dimensional nonprojectable graphic
m Computer file
o Kit
p Mixed material
r 3-dimensional artifact or naturally occurring object
t Manuscript language material
07   Bibliographic Level (BLvl)
a Monographic component part
b Serial component part
c Collection
d Subunit
i Integrating resources
m Monograph or single manuscript
s Serial
08   Type of Control (Ctrl)
Blank No specified type
a Archival
09   Character Coding Scheme
Blank MARC-8
a UCS/Unicode
10 2

Indicator Count

  • Number of character positions reserved for indicators

Bytes 11-21

Byte Value Definition
11 2

Subfield Code Count

  • Number of character positions reserved for a subfield code
  • Code = delimiter (‡) and a letter or a number

Base Address of Data

  • 5-character number = length of the leader and the directory including the field terminator
  • Right-justified with leading zeros
  Encoding Level (ELvl)
Blank Full-level
1 Full-level, material not examined
2 Less-than-full-level, material not examined
3 Abbreviated level
4 Core-level
5 Partial (preliminary) level
7 Minimal-level
8 Prepublication level
I Full-level input by OCLC participants
J Deleted record
K Minimal-level input by OCLC participants

Added from a batch process

 Note: Value obsolete

M Added from a batch process

  Descriptive Cataloging Forms (Desc)
Blank Non-ISBD
c ISBD Punctuation Omitted
n Non-ISBD Punctuation Omitted
u Unknown
  Linked Record Requirement
Blank Related record not required
20 4

Length of the Length-of-Field Portion

  • Number of characters in the length-of-field portion of a directory entry
21 5

Length of the Starting-Character-Position Portion

  • Number of characters in the starting-character-position portion of a directory entry

Bytes 22-23

Byte Value Definition

Transaction Type Code in Hexadecimal (OCLC defined)

  • Information coded in hexadecimal except for Values Blanke, and x used for exported records

 Note: For historical information and a complete list of codes, see field 994.

Prior to Nov. 12, 2006 X'01'


  • Produce catalog cards for main holding library or first holding library in 049 field
  • Set location symbol in WorldCat


  • Set location symbol without producing catalog cards

Delete Holdings

  • Remove location symbol through a Cancel Update or a Delete Holdings command


  • Replace WorldCat record without producing catalog cards
  • Records with this transaction type code contain no local data fields (009, 049, 059, 098, 099, 590, 910, and 94x)

All Produce

  • Produce catalog cards for every holding library in 049 field and set location symbol in WorldCat

Offline Retrieve

  • Offline use of the record without setting the location symbol

Offline Update

  • Set location symbol

Offline Delete Holdings

  • Remove location symbol
Blank Exported via CORC
e Exported via Cataloging or OCLC Selection
x Exported via OCLC Arabic Cataloging software, OCLC CatCD for Windows, OCLC CatME™ for Windows, or OCLC CJK™ software
After Nov. 12, 2006 0 Transaction codes are stored in field 994. This change is present in all bibliographic records output from OCLC systems (Connexion client 1.60 stored transaction codes in field 994 and in Leader Byte 22).
23 0 Undefined