Introduction

Like other cataloguing systems, "BWJM Numbers" describe the features of a coin.

BWJM Numbers help collectors describe a coin in a simple and concise way without having to share photos or describe the coin in a manner that may not be clear to others.

BWJM Numbers identify the following features:

Variety of counterfeit (Camel Toe vs. Montreal Mint, Z Dollard or Double Canada)
Year of coin
Rotated dies
Die clashes
Obverse and reverse die cracks
Other defects (eg: weak strike, excess die metal)

Each component of the code is separated by a hyphen for readability.

Codes Used

Variety of Counterfeit	Camel Toe: "CT" Montreal Mint: "MTL" Z Dollard: "ZD" Double Canada: "DC"
Year of Coin	Use the last two digits only Combined with variety of counterfeit without hyphen (eg: "CT06") Use "A" suffix for "serif" obverse variety (eg: "CT05A")
Rotated Dies	Rotations of up to ±15° are common and not catalogued "RD" followed by angle of rotation Example: "RD340", "RD065" Angles are measured from 0° at the top going clockwise
Die Clashes	Obverse: "OC1", "OC2", etc. Reverse: "RC1", "RC2", etc.
Obverse Die Cracks	Identified by a number: "1", "2", etc. Numbers are grouped by year Progressive cracks identified with lowercase letters: "3a", "3b", etc.
Reverse Die Cracks	Identified by a letter: "A", "B", etc. Progressive cracks identified by a number: "E1", "E2", etc.
Weak Strikes	"WS"
Excess Die Metal	"EM"

Examples

CT02-OC2-A	Camel Toe, 2002 Obverse die clash "OC2" Reverse die crack "A"
CT05-RD025-E3	Camel Toe, 2005 Clockwise 25° rotated dies Reverse die crack "E3"
MTL05	Montreal Mint, 2005
CT06-1-C	Camel Toe, 2006 Obverse die crack "1" Reverse die crack "C"