Beginning in 1905, Germany began phasing in the use of watermarked paper on its new issues. Many color and perforation variations exist, primarily due to differences in peacetime and wartime printings.
These issues can be distinguished from previous Yacht Issues by the units of currency and the watermarks:
1901: Pesa/Rupien values, no watermark
1905: Heller values, no watermark
1905/1920: Heller/Rupien values, lozenge watermark
The copies of MiNr. 38 I A a and MiNr. A 38 I shown above are examples of Plate Flaw I, retouching in the clouds at upper left: