Wellsville China Date Codes

Some pieces are date coded but most are not. Date codes could be marked with a four-digit number that represents the year so 1951 would be made in 1951. There are some pieces that could be marked with a two-digit code that represents the last two digits of the year so 51 would be made in 1951.
 
A letter (dash) number code is also used but it has not been deciphered as of yet.
Examples of a 4 digit code:
Year/Month
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
January-December
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
Year/Month
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
January-December
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
Year/Month
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
January-December
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
Year/Month
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
January-December
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
Year/Month
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
January-December
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
Year/Month
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
January-December
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
Year/Month
1962
1963
1964
1965
1966
1967
1968
1969
January-December
1962
1963
1964
1965
1966
1967
1968
1969
Examples of a 2 digit code:
Year/Month
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
January-December
02
03
04
05
06
07
08
09
10
11
Year/Month
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
January-December
12
13
14
15
16
17
18
19
20
21
Year/Month
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
January-December
22
23
24
25
26
27
28
29
30
31
Year/Month
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
January-December
32
33
34
35
36
37
38
39
40
41
Year/Month
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
January-December
42
43
44
45
46
47
48
49
50
51
Year/Month
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
January-December
52
53
54
55
56
57
58
59
60
61
Year/Month
1962
1963
1964
1965
1966
1967
1968
1969
January-December
62
63
64
65
66
67
68
69

Notes: Date code may or may not contain a (dash)