Here is an assortment of playful Japanese postcards from the late 19th and early 20th centuries, found in a recent book by collector Hiroki Hayashi entitled "Antique Cute Post Cards in Japan" (Nippon no kawaii ehagaki).

Vintage Japanese postcards --
Betty Boop (Yamaguchi Seikyokudo Co., Ltd. - c. 1930s)

Vintage Japanese postcards --
Betty Boop (1937)

Vintage Japanese postcards --
Betty Boop, Mickey and Minnie (1936)

Vintage Japanese postcards --
Mickey (c. 1920s-40s)

Vintage Japanese postcards --
Kewpie Mayonnaise ad (1932)

Vintage Japanese postcards --
Kewpie (c. 1920s-40s)

Vintage Japanese postcards -- Vintage Japanese postcards --
Kewpie (1933/1935)

Vintage Japanese postcards --
Kewpie (c. 1920s-40s)

Vintage Japanese postcards --
Kewpie (Shoseido - 1919)

Vintage Japanese postcards --
Kewpie (Shoseido - 1919)

Vintage Japanese postcards --
Kewpie (c. 1920s-40s)

Vintage Japanese postcards --
Kewpie (c. 1920s-40s)

Vintage Japanese postcards --
"Bring it on" (Propaganda card by Kiyoshi - 1940)

Vintage Japanese postcards --
"I've got your back" (Military Mail greeting card for troops - 1940)

Vintage Japanese postcards --
Dancing skeletons (c. 1890s-1900s)

Vintage Japanese postcards --
Yoshikawa Roppa (Hibiya Yurakuza Theater - 1940)

Vintage Japanese postcards --
New Year's Card (1911)

Vintage Japanese postcards --
Muscles and blood vessels (1920)

Vintage Japanese postcards --
Standing in flames (Shokichiro Yamaguchi - c. 1920s)

Vintage Japanese postcards --
Postcard commemorating Children's Expo (Dobunkan - 1906)

Vintage Japanese postcards --
One in a series of naughty joke cards (Toyo Postcard Association - c. 1900s-10s)

Vintage Japanese postcards --
Harunaa beauty products (c. 1920s-1940s)

Vintage Japanese postcards --
Single-wheeled vehicle (1936)

Vintage Japanese postcards --
Norakuro (Suiho Tagawa - c. 1930s)

Vintage Japanese postcards --
Marriage and the growing use of X-ray machines - (c. 1910s)

Vintage Japanese postcards --
Dancing cats (c. 1920s-1940s)