Jeweler Miki Corp. filed for bankruptcy protection Wednesday with liabilities estimated at ¥11.7 billion on slumping sales at its stores throughout Japan, Tokyo Shoko Research said Wednesday.

The company, known for Jewelry Maki and other nationwide jewelry shop chains, filed an application with the Tokyo District Court for protection under the Civil Rehabilitation Law, the credit research agency said.

Miki had tried to restructure under the burden of heavy debts accompanying the development of a large number of shops. In the year to last August, however, sales plunged to ¥20.5 billion from a peak of almost ¥200 billion.

The sales slump grew even more serious when the economy deteriorated in the fall.