SHENYANG, June 15 -- More than 300 clay coins issued by the "Manchukuo" are being exhibited at a museum in Shenyang City, capital of northeast China's Liaoning Province, a stark reminder of looting by Japanese invaders.

The clay coins, which were donated to the museum by collector Shi Hongxing, bear the word "Manchukuo", which from 1931 to 1945 was a puppet regime created across China's northeastern provinces by the Japanese invaders.

Shi said that after the Sept. 18 Incident in 1931, Japanese invaders repurposed items made from metal, such as coins, to produce fire arms. As metal was in such short supply, the Japanese issued these clay coins.

"The clay coins are rare as they are prone to be worn out. They are indelible evidence of Japan's economic invasion," Shi said.