Japanese Stamps Digital Museum

田沢型旧大正毛紙切手 << 1914年(大正3年) ~ 1925年(大正14年) >> みほん 1-4-2

Tazawa type old kegami stamps - Specimen -
Issued on 1914(taisyo3) - 1925(taisyo 14)

Old Taisho kegami Stamps Issued on 1914(taisyo3) - 1925(taisyo 14) - Specimen - In 1914 (Taisho 3), the Ministry of Communications issued stamps of the Art nouveau design with 'Kegami' and 'Sukashi' on the mount of the Tazawa-type stamps issued the previous year to strengthen the prevention of counterfeiting. 'Kegami' is a paper that is made by putting straw or cotton fiber into the backing paper. 'Sukashi' is a pattern that appears on paper when exposed to light and can be distinguished from others.

------------
The above is only true for specimen stamps.
For more information and official printed stamps, see this.
------------