Signatures and date codes
used by Karl Martz
on the pottery he made.

Feedback to Eric Martz.

Most photographs of pots on this page were taken by Eric Martz in 2001 from pots in his possession. These pots were given to Eric by Karl and Becky prior to Karl's death in 1997, and hence are known to be authentic. Some photos provided by others are judged to be of authentic Karl Martz pots based on the signature, style of the pot, and quality of work. Click on the bottoms to see the tops and other information about individual pots! See also:

Ceramics signed only "Martz" or "MARTZ" (no first name) are usually by Gordon Martz and Jane Marshall Martz. Their older pieces usually have letter-number codes (examples). Works by Karl Martz usually have his full name, his initials KM (usually stylized in a circle as shown below), or "Martz Studio" (which was never used by Gordon and Jane [personal communication with Jane Marshall Martz, 2002]). "Martz Studio" signatures that include an overlapping BB are by Becky Brown (examples).

Karl first studied ceramic art at Ohio State University in the summer of 1931 (more).

In 1934, while an apprentice at the Brown County Pottery, Karl began signing his pots with his initials "KM" fitted into a circle. (Neither Karl, nor his father, nor his sons were given middle names.) When Karl and Becky set up the Karl Martz Studio in 1936, he continued using the circled KM, and this remained his primary signature throughout his career.

Karl made a few pots at the Brown County Pottery signed simply "The Pottery, Brown County" or "Brown County Pottery", apparently before he adopted the circled KM. The signature at left is from a pot Karl described as his first at the Brown County Pottery. The one at right is from a pitcher shown in a 1934 photograph of him working at the Brown County Pottery.
"KM" above was added many years later
with a permanent marker.
Even after he began using the circled KM, he sometimes simply wrote "Karl Martz" in block print, as shown in this example from the Brown County Pottery in 1935, or in script (far right, ca. 1940). (Compare with the earlier 1934 example above that includes a circled KM.)

Here are two circled KM examples from the 1940's.

Beginning about 1949 or 1950, Karl and Becky began including "Martz Studio" on their pots. This referred to the studio they built in Brown County. Pots signed with the circled KM were made, decorated and glazed by Karl; pots signed BB or Becky Brown were made, decorated and glazed by Becky Brown.

In 1957, Karl visited the traditional Jugtown Pottery in North Carolina for about 10 days, during which he made a number of salt-glazed pots. Most have a "J" near the signature. Click the signature to see some of these pots and a link to Karl's account of his visit.

(See serial numbers on paper rectangles.)
From about 1960 through the early 1980's, Karl stopped putting the year on his pots (see Dates and year codes).

Some pots made during (or possibly shortly after) his sabbatical to Kyoto, Japan in 1963-64 (see timeline) were signed with a circled KM plus japanese characters meaning "Japan" (Nippon -- country of the rising sun). Some pots made during his sabbatical in Mashiko, Japan, in 1971-72 were signed with KM (no incised circle) on one side near the foot, plus an "M" (for Mashiko) on the opposite side near the foot.

Through the 1950's, Karl typically incised the circled KM into the clay by hand, with a sharp metal stylus. Probably in the 1960's, he began making signature stamps from fired clay, with which the signature was impressed into the still-plastic foot. The stamping tools were often passed through more than one cycle of positive and negative stamping, drying and firing, resulting in substantial shrinkage and miniaturization. Sometimes, the stamp was made in a small ball of clay pressed onto the surface of the pot, as shown at right.

The circled KM was typically on the bottoms of the pots through the 1950's. Later, on upright forms, he often put the signature low on the side.

Beginning probably in the 1970's, Karl used alternative signatures on some pots. He began reserving his circled KM cachet for his more impressive "show" pieces. He continued to enjoy making simple utilitarian mugs, pitchers, bowls, and covered jars, and these were sometimes signed with a plain "KM" (not circled), "CP" for "Clayburn Pottery", "Studio M", or "Kiln Haus". The latter three were typically stamped.

Dates and Year Codes

Through the 1950's Karl usually included the year on the bottoms of the pots. Around 1960, he decided he would rather not reveal the actual year he made a pot, so that would not be an issue when work was submitted to shows. Probably most of his pots made in the 1960's and 1970's were undated. About 1982, Karl adopted a secret cuneiform code for indicating the year, and also the serial number of each pot within the year. In order to read these codes, one should orient the circled KM at the top. The year will then be at the left, and the serial number at the right.

Using the chart below, it can be seen that the pot at the right was the 18th pot Karl made in 1987.

Karl began coding dates about 1982. In the early 1990's, Karl gave a verbal description of his secret coding system to son Eric, who made written notes. There are a number of uncertainties, but the general scheme is clear. The variations shown below are Eric's guesses from his written notes -- perhaps not all these variations were actually used. In his symbols for the digits 6 through 9, it was immaterial whether the branches extended to the right, to the left, or both, and whether they angled up or down.

The first year, Karl indicated only the serial number for that year, but not the year. It is not certain what the "first year" was. (We would appreciate receiving photos of pots with examples of cuneiform date codes from the early 1980's.) After the first year, he began indicating the second digit of the year (e.g. "3" for 1983, "9" for 1989) plus the serial number. One case is known in which 1990 was indicated with a horizontal bar (for the digit zero, see below). Whether all 1990 pots were indicated consistently in this way is not certain. Beginning in 1991, both digits of the year are indicated. 1992 may have been the last year Karl made pots -- one example is known coded 1992, serial number 27 (not shown). If anyone knows of a pot coded later than 1992, please let me know.

The year and serial number were assigned at the time the body was made. In some cases, glazing and final firing may have been completed a year or more later.

Digit codes (illustrated above):