Appendix C. Leadhead Codes

A.
Leadhead Grouping
1.
Methods that have a first leadhead that is the same as one of the leadheads found in the Plain Course of Plain Bob or Grandsire have been assigned a code according to the order in which the leadheads occur in its Plain Course. They are a useful shorthand for communicating the Lead order of a Method.
Originally lowercase letters were ascribed and these were later extended with numbers to cover higher stages. In the Framework the codes associated with the letters p, q, r and s have been renumbered to include the leadheads previously omitted before the Differential classes were added.
Methods with Plain Bob leadheads are split into different leadhead groups according to the place notation (where n is the Stage) immediately before the leadhead as follows:
Methods with Grandsire leadheads whose hunt bells have the same path are split into different leadhead groups according to the place notation (where n is the Stage) immediately after the leadhead as follows:
Any methods not falling in the above groupings are not given a leadhead code even if they have Plain Bob or Grandsire leadheads.
B.
Plain Bob Leadhead Codes for Even Stages
LH CodeMinimusMinorMajorRoyalMaximusFourteenSixteen
PN12PN1n
ag134213526413527486135274960813527496E8T013527496E8A0BT13527496E8A0CTDB
bh156342157382641573920486157392E4T608157392E4A6B8T0157392E4A6C8D0BT
cj1785634217950382641795E3T204861795E3A2B4T6081795E3A2C4D6B8T0
c1j1190785634219E7T503826419E7A5B3T2048619E7A5C3D2B4T608
c2j21ET9078563421EA9B7T50382641EA9C7D5B3T20486
c3j31ABET9078563421ACED9B7T5038264
c4j41CDABET907856342
d4k41DBCTA0E89674523
d3k31BTA0E896745231BTD0C8A6E492735
d2k21T0E896745231T0B8A6E4927351T0B8D6C4A2E3957
d1k11089674523108T6E492735108T6B4A2E3957108T6B4D2C3A5E79
dk18674523186049273518604T2E395718604T2B3A5E7918604T2B3D5C7A9E
el1645231648273516482039571648203T5E791648203T5B7A9E1648203T5B7D9CEA
fm1423142635142638571426385079142638507T9E142638507T9BEA142638507T9BEDAC
C.
Plain Bob Leadhead Codes for Odd Stages
LH CodeDoublesTriplesCatersCinquesSextuplesSeptuplesOctuples
PN12nPN1
pr13524135274613527496813527496E8013527496E8A0T13527496E8A0CTB13527496E8A0CTFBD
p1r1154321573624157392846157392E4068157392E4A6T80157392E4A6C8B0T157392E4A6C8F0DTB
p2r217654321795836241795E3028461795E3A2T40681795E3A2C4B6T801795E3A2C4F6D8B0T
p3r319876543219E7058362419E7A5T30284619E7A5C3B2T406819E7A5C3F2D4B6T80
p4r41E0987654321EA9T705836241EA9C7B5T3028461EA9C7F5D3B2T4068
p5r51ATE0987654321ACEB9T705836241ACEF9D7B5T302846
p6r61CBATE0987654321CFADEB9T70583624
p7r71FDCBATE098765432
q6s61DBFTC0A8E6947253
q5s51BTC0A8E69472531BTD0F8C6A4E29375
q4s41T0A8E69472531T0B8C6A4E293751T0B8D6F4C2A3E597
q3s3108E6947253108T6A4E29375108T6B4C2A3E597108T6B4D2F3C5A7E9
q2s218694725318604E2937518604T2A3E59718604T2B3C5A7E918604T2B3D5F7C9AE
q1s116472531648293751648203E5971648203T5A7E91648203T5B7C9AE1648203T5B7D9FECA
qs142531426375142638597142638507E9142638507T9AE142638507T9BECA142638507T9BEDAFC
D.
Grandsire Leadhead Codes for Odd Stages
LH CodeDoublesTriplesCatersCinquesSextuplesSeptuplesOctuples
PN3PNn
ag12534125374612537496812537496E8012537496E8A0T12537496E8A0CTB12537496E8A0CTFBD
bh1275634127593846127593E4068127593E4A6T80127593E4A6C8B0T127593E4A6C8F0DTB
cj1297856341297E5038461297E5A3T40681297E5A3C4B6T801297E5A3C4F6D8B0T
c1j112E9078563412E9A7T50384612E9A7C5B3T406812E9A7C5F3D4B6T80
c2j212AET9078563412AEC9B7T50384612AEC9F7D5B3T4068
c3j312CABET9078563412CAFED9B7T503846
c4j412FCDABET90785634
d4k412DFBCTA0E8967453
d3k312BCTA0E896745312BDTF0C8A6E49375
d2k212TA0E896745312TB0C8A6E4937512TB0D8F6C4A3E597
d1k1120E8967453120T8A6E49375120T8B6C4A3E597120T8B6D4F3C5A7E9
dk12896745312806E4937512806T4A3E59712806T4B3C5A7E912806T4B3D5F7C9AE
el12674531268493751268403E5971268403T5A7E91268403T5B7C9AE1268403T5B7D9FECA
fm124531246375124638597124638507E9124638507T9AE124638507T9BECA124638507T9BEDAFC
E.
Grandsire Leadhead Codes for Even Stages
LH CodeMinimusMinorMajorRoyalMaximusFourteenSixteen
PN3nPN-
pr12536412537486125374960812537496E8T012537496E8A0BT12537496E8A0CTDB
p1r1127583641275930486127593E4T608127593E4A6B8T0127593E4A6C8D0BT
p2r212970583641297E5T304861297E5A3B4T6081297E5A3C4D6B8T0
p3r312E9T705836412E9A7B5T3048612E9A7C5D3B4T608
p4r412AEB9T705836412AEC9D7B5T30486
p5r512CADEB9T7058364
q6s612DCBATE09876543
q5s512BATE0987654312BDTC0A8E694735
q4s412TE0987654312TB0A8E69473512TB0D8C6A4E3957
q3s31209876543120T8E694735120T8B6A4E3957120T8B6D4C3A5E79
q2s212876543128069473512806T4E395712806T4B3A5E7912806T4B3D5C7A9E
q1s11265431268473512684039571268403T5E791268403T5B7A9E1268403T5B7D9CEA
qs1243124635124638571246385079124638507T9E124638507T9BEA124638507T9BEDAC
F.
Alternative Leadhead Code System
1.
As an alternative to the letter codes shown above, Methods with Plain Bob Leadheads can be coded according to the number of Plain Leads of Plain Bob that it takes to reach the same Leadhead as it does with one Plain Lead of the Method in question.
Example 1: The first Leadhead of Cambridge Surprise Major is 15738264. This same Leadhead would be reached by ringing two Plain Leads of Plain Bob Major. Cambridge Surprise Major is therefore referred to as a "+2" Method.
Example 2: The first Leadhead of London Surprise Minor is 142635. This same Leadhead would be reached by ringing four Plain Leads of Plain Bob Minor. Going forward for four Plain Leads of Plain Bob Minor reaches the same Leadhead as going backwards for one Plain Lead, so London Surprise Minor is referred to as a "-1" method.
Pluses are used up to and including the halfway point of a Plain Course of Plain Bob, and minuses are used after the halfway point of the Plain Course. So in Minor, the codes would range from -2 to +2, in Triples the codes would range from -2 to +3, in Major the codes would range from -3 to +3, and so on.
For Plain Bob Leadhead Methods where nth's Place rather than 2nd's Place is made at the Leadend Change (where n is the Stage), the letter 'n' is added to the code.
Example 3: The first Leadhead of Bristol Surprise Major is 14263857 and Bristol S Major is an 8th's Place Leadend Method. Bristol S Major is therefore referred to as a "-1n" Method.
Methods that have one Plain Lead in their Plain Course are referred to as "+0" Methods.
Note that this alternative Leadhead code system is usually only used for Plain Bob Leadhead Methods with even Stages, and not for Plain Bob Leadhead Methods with odd Stages, nor for Grandsire Leadhead Methods.
2.
The following tables show the mapping between the codes shown in Appendix C.B above and the alternative Leadhead codes:
Appendix C.B codeAlternative Leadhead code
a+1
b+2
c+3
c1+4
c2+5
c3+6
c4+7
d4-7
d3-6
d2-5
d1-4
d-3
e-2
f-1
Appendix C.B codeAlternative Leadhead code
g+1n
h+2n
j+3n
j1+4n
j2+5n
j3+6n
j4+7n
k4-7n
k3-6n
k2-5n
k1-4n
k-3n
l-2n
m-1n