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Duplex Cancellations of Canada


Postal regulations required that an envelope be postmarked and that the stamp be cancelled. This would usually be accomplished by striking the envelope twice, once with a datestamp and once with an obliterator. The duplex device simplified this process by requiring only one strike per envelope.

The database classifies all such cancellations by listing number, identifies each by wording, type and size. It also defines the period of use with earliest and latest known dates, known timemarks.

A duplex hammer (struck exactly as you would a hammer) is composed of two parts: the dater, to indicate the office of origin, province, month and day and sometimes a timemark, and the obliterator (or killer) normally of horizontal bars in varying numbers used to render the stamp unusable a second time. These two parts are most commonly made from one piece of steel, but can sometimes be made of two separate pieces welded together, as was done with the A types.

Duplex hammers were first introduced in Great Britain in 1853 as a result of increased volumes of mail and the desire to speed up its handling. Canada's first duplex hammers were manufactured by D. G. Berri in England and placed in service in 1860. These cancellations are commonly called ''Berri''. Several different types of duplex have evolved from this and have been in use in Canada since then, but they are slowly disappearing due to replacement by rubber POCON (Post Office Computer Organization Number) datestamps and machine cancellations among others. Smaller offices here and there still use the mighty duplex hammer.

Collectors are fortunate to have available for study the Pritchard & Andrews as well as the Canada Post Office proof impression books covering the period 1876 to 1953, except for the period May 1895 to July 1907, which are missing from the Pritchard & Andrews proof impression books. These original proof impression books are available at the National Library and Archives and additionally through a series of books edited by J. Paul Hughes, published by Robert A. Lee Philatelist Ltd. and now available through Gary J. Lyon at Eastern Auctions Ltd.

In addition to the duplex cancelling devices issued by the Post Office, some postmasters chose to manufacture their own. Some combined two official devices and some combined an official device and one handmade of cork, wood or metal. These interesting oddities are listed and described in the Unofficial Duplexes section.

A typical duplex hammer. An example of a duplex handstamp.
© Musée canadien des civilisations,
1974.998.97 S96-01205.
Self-inking duplex device.
© Musée canadien des civilisations,
1974.1081.1 D2004-29394.

Explanation of Database Columns

NUMBER: (Catalogue number)

The "D" refers to duplex; the next two letters are either the provincial or category abbreviations. The numbers are sequential, with occasional spaces left for additional listings. A number followed by a small letter, e.g. DBE-14a, indicates a sub-listing and not a separate hammer. A number followed by a capital letter, e.g. DON-30A, indicates a separate hammer added later when a new number was not available. A missing number could indicate either it was left for a possible entry, or it was removed for different reasons.


Alphabetical and chronological listing of all recorded duplex instruments. The symbol "/" separates the wording at the top of the hammer from the wording at the bottom, e.g. "TORONTO/·CANADA·." Using this example, the two middle dots at either side of CANADA are called side dots and are seen right and left of the bottom part of the dater, and there is an additional period after "CANADA". Two-part town names can sometimes be separated by either "-", ".", or "·" hyphens, periods or dots. All these are very important to note for proper hammer identification.


The roman numerals here refer to the dater type. We note that this historical nomenclature differs from that used in the Broken Circles and CDS databases, but we trust that it will not cause confusion here.
  • I - Split or broken circle
  • II - Full or unbroken circle (CDS)
  • III - Double split or broken circle
  • IV - Full circle enclosing a broken circle
  • V - Other


The letter followed by a number refers to the obliterator or killer type and the number of bars it contains. For example, "B11" indicates an oval killer with eleven unbroken horizontal bars.

  • Horizontal unbroken bars:
    • A - Circular
    • B - Oval
    • C - Other
  • Vertical unbroken bars:
    • D - Circular
    • E - Oval
    • F - Other
  • Horizontal broken bars:
    • G - Circular
    • H - Oval
    • J - Other
  • Vertical broken bars:
    • K - Circular
    • L - Oval
    • M - Other
  • Wavy line oval bars:
    • N- Convex curve ends up
    • O - Convex curve ends down
  • Vertical CANADA (~3mm in between dater and wavy line killer)
    • P - Convex curve with ends up
    • Q - Convex curve with ends down
  • Vertical CANADA (~2.5mm in between dater and wavy line killer)
    • R - Convex curve ends up
    • S - Convex curve ends down
  • Wavy line broken by letter
    • T - Convex curve ends up or number
    • U - Convex curve ends down
  • Symbols
    • V - Target
    • W - Star
    • X - Boxed
    • Y - Intaglio letter
    • Z - Other


Refers to the diameter of the dater in millimetres, measured horizontally across the widest portion. These measurements are prone to minute differences caused by poor inking, overinking, paper absorption, impression struck at an angle, etc.


Where registered in the proof ledgers this is the date appearing in the indicia.
"N.I.P.B." indicates 'Not In Proof Books.' A blank space indicates proofed, but with no precise indication of when. In this case there will usually be a note in the Remarks column indicating the approximate month and year of the impression. It should be noted that the period May 1895 to July 1907 is missing from the Pritchard and Andrews proof impression books.


Indicates the earliest recorded (reported) date of use.


Indicates the latest recorded (reported) date of use.


Timemarks recorded. This column does not include timemarks seen in the proof impression. Includes AM, PM, AP (probably French for après-midi), BLANK (no timemark), NT (night), numerals (1, 2, 3, etc.), hours (10AM, 2:30PM) and letters (A, B, C, etc.). Where no timemark is known, an empty space will be seen.


This column contains information intended to help the reader identify a particular duplex. What can be seen here includes: killer dimensions (height × width in millimetres); differences in lettering sizes, styles or spacing; width of a given group of letters, e.g. "SASK." is a measurement from the left of the first 'S' to the period after the 'K'; In this section, "f.a.l." means "from at least". In this section, no attempt has been made to list all the different time mark variations such as reversed, TM at top or bottom, as they are plentiful, and can often change many times in a given number of years for one given duplex.

Bibliography and Acknowledgments

The first two editions of the Catalogue of Canadian Duplex Catalogues were produced by Robert A. Lee. The database presented here originated in the third edition of the catalogue, produced by Stéphane Cloutier. Important contributions were made by many collectors over the years, particularly by members of the BNAPS Duplex Study Group. In addition, the early work of E. A. Smythies, the father of Canadian duplexes, should be also acknowledged.

The Canadian Postal Archives provided the proof impressions for the series of books Proof Strikes of Canada edited by the late J. Paul Hughes. The three books covering the duplex proof impressions have been a major contributor to the catalogues and database. The Canadian Postal Museum allowed the viewing of photographing of their collection of duplex cancellers, and some of these photographs are reproduced here with permission.