Belongs to: Joost Thooft
Joost Thooft, owner of De Porceleyne Fles, 18761884 (factory mark is still being used)
The mark  a figurative sign of a bottle and the letters JT  has been used by De Porceleyne Fles/Royal Delft since 1879. The year marks and painter's initials also provide more information about an object. In addition, the checksums or article numbers are sometimes included.
The year marks consist of one or two letters that represent the year of production. Below you can find an overview of the year marks of De Porceleyne Fles. The painter signed the piece with his or her initials. Unfortunately, not all initials have been identified, but an overview of the known signatures or initials can also be found on the website of Royal Delft (De Porceleyne Fles).
(source: How do I recognize an authentic Royal Delft piece?)
A 
1879 
AA 
1905 
BA 
1931 
CA 
1956 
DA 
1981 
EA 
2006 
B 
1880 
AB 
1906 
BB 
1932 
CB 
1957 
DB 
1982 
EB 
2007 
C 
1881 
AC 
1907 
BC 
1933 
CC 
1958 
DC 
1983 
EC 
2008 
D 
1882 
AD 
1908 
BD 
1934 
CD 
1959 
DD 
1984 
ED 
2009 
E 
1883 
AE 
1909 
BE 
1935 
CE 
1960 
DE 
1985 
EE 
2010 
F 
1884 
AF 
1910 
BF 
1936 
CF 
1961 
DF 
1986 
EF 
2011 
G 
1885 
AG 
1911 
BG 
1937 
CG 
1962 
DG 
1987 
EG 
2012 
H 
1886 
AH 
1912 
BH 
1938 
CH 
1963 
DH 
1988 
EH 
2013 
I 
1887 
AI 
1913 
BI 
1939 
CI 
1964 
DI 
1989 
EI 
2014 
J 
1888 
AJ 
1914 
BJ 
1940 
CJ 
1965 
DJ 
1990 
EJ 
2015 
K 
1889 
AK 
1915 
BK 
1941 
CK 
1966 
DK 
1991 
EK 
2016 
L 
1890 
AL 
1916 
BL 
1942 
CL 
1967 
DL 
1992 
EL 
2017 
M 
1891 
AM 
1917 
BM 
1943 
CM 
1968 
DM 
1993 
EM 
2018 
N 
1892 
AN 
1918 
BN 
1944 
CN 
1969 
DN 
1994 
EN 
2019 
O 
1893 
AO 
1919 
BO 
1945 
CO 
1970 
DO 
1995 
EO 
2020 
P 
1894 
AP 
1920 
BP 
1946 
CP 
1971 
DP 
1996 
EP 
2021 
Q 
1895 
AQ 
1921 
BQ 

CQ 

DQ 

EQ 

R 
1896 
AR 
1922 
BR 
1947 
CR 
1972 
DR 
1997 
ER 
2022 
S 
1897 
AS 
1923 
BS 
1948 
CS 
1973 
DS 
1998 
ES 
2023 
T 
1898 
AT 
1924 
BT 
1949 
CT 
1974 
DT 
1999 
ET 
2024 
U 
1899 
AU 
1925 
BU 
1950 
CU 
1975 
DU 
2000 
EU 
2025 
V 
1900 
AV 
1926 
BV 
1951 
CV 
1976 
DV 
2001 
EV 
2026 
W 
1901 
AW 
1927 
BW 
1952 
CW 
1977 
DW 
2002 
EW 
2027 
X 
1902 
AX 
1928 
BX 
1953 
CX 
1978 
DX 
2003 
EX 
2028 
Y 
1903 
AY 
1929 
BY 
1954 
CY 
1979 
DY 
2004 
EY 
2029 
Z 
1904 
AZ 
1930 
BZ 
1955 
CZ 
1980 
DZ 
2005 
EZ 
2030 