Hankyu Department Stores Inc. and Hanshin Department Store Ltd. said Friday they have agreed to form a comprehensive business alliance ahead of their parent companies' Oct. 1 merger.

The two retail chains will consider specific cooperation plans after their Osaka-based parents -- Hankyu Holdings Inc. and Hanshin Electric Railway Co. -- merge under a new holding company.

They intend to draw up detailed plans by March and implement them in April. Each will own 20,000 shares in the other.

The chains' parent companies, Hankyu Holdings and Hanshin Electric Railway, agreed to tie up in May to prevent a hostile takeover bid by financier Yoshiaki Murakami for Hanshin.

In June, the Murakami fund terminated its bid, agreeing to sell most of its stake in Hanshin Electric Railway to Hankyu Holdings. Murakami later was arrested on suspicion of insider trading in an unrelated case.

The Hankyu-Hanshin group will be the third-largest Japanese railway outside the nationwide Japan Railway group.