Photo/Illutration The postmark for Oct. 1, 1900, the day the issuance of privately designed postcards was approved in Japan (Provided by Hitoshi Takao)

KYOTO--A picture postcard with an Oct. 1, 1900, postmark, the date the issuance of privately designed postcards was legally approved in Japan, is causing a stir among collectors because of its exceptional rarity.

It is the “phantom postcard” that avid collector Hitoshi Takao in Kyoto had yearned to add to his massive collection.

Experts said the item symbolizes the start of picture postcards, which exponentially spread in Japan following their approval.

The 120-year-old postcard was sent with a 1.5-sen stamp, a fraction of 1 yen. The back side depicts what appears to be a lighthouse along a stretch of coast but with no writing.

The handmade postcard measures 14.3 centimeters by 9 cm, slightly smaller than the “nengajo” New Year’s greeting postcard currently issued by Japan Post Co.

Takao, 71, an adviser to a printing company, purchased the item for an undisclosed sum at an auction in Tokyo in July to add to his collection of more than 50,000 postcards that took 20 years to assemble. He had long been convinced that a postcard stamped on the first day of approval must exist.

The postcard was seemingly sent self-addressed by a pawnshop operator in the capital to mark the start of privately designed postcards.

The previously known oldest privately made postcard in existence after the approval was one issued Oct. 5, 1900, which came with the boys’ magazine “Kinsei Shonen” (Modern boys) and portrays two boys blowing soap bubbles.

Akira Yahara, an adviser to the Japan Picture Postcard Society comprising experts and collectors, called the postcard with an Oct. 1, 1900, postmark “significant to the study of the history of picture postcards.”

“The material heralded the start of picture postcard culture flourishing in Japan,” said Yahara, 79.

Kenji Sato, a sociology professor at the University of Tokyo who has a keen interest in the history of picture postcards, noted that it is “rare” for a picture postcard postmarked on the first day when privately designed postcards were approved to emerge after so many decades.

“Many people had already begun collecting postcards for pleasure at the time, and an individual apparently sent the self-addressed missive to receive the postmark of the first day,” he said. “It is interesting that it has survived for 120 years.”