Taishukan Publishing Co. violated industry rules by providing free classroom materials to schools that agreed to use its English textbooks this year, the publisher and the education ministry disclosed Friday.

The Tokyo-based publisher denied intentionally providing the materials to the public and private high schools and said its employees did so at their own discretion. About 1,500 sets of study materials were distributed, at a cost of ¥290 ($3) each.

The Textbook Publishers Association of Japan, headed by Taishukan President Kazuyuki Suzuki since February, bans companies from providing cash and goods, including teaching materials, to individuals involved in the textbook selection process to ensure fair competition.