Workers represented by a labor union at Japanese department store operator Sogo & Seibu Co. will go on a rare strike at its flagship store in Tokyo, as its parent company remains committed to selling the chain to a U.S.-based investment fund despite their opposition to the buyout, the union said Wednesday.

In the first such action by a major department store union in 61 years, around 900 union members at the Seibu Ikebukuro store will refrain from working on Thursday, the union said.

In remarks to reporters, union head Yasuhiro Teraoka sought understanding from shoppers and business partners to "please allow the store to close for just a day" to ensure the ongoing survival of Sogo department stores.

File photo taken in June 2022 shows the Seibu Ikebukuro department store in Tokyo. (Kyodo)

Despite the union's concerns about its members' future, parent company Seven & i Holdings Co. plans to approve the sale of the struggling department store chain at a board meeting on Thursday to Fortress Investment Group LLC, sources close to the matter said.

The business is expected to sell for over 200 billion yen ($1.36 billion) on Friday once Seven & i's board finalizes the sale plan at its meeting. Seven & i President Ryuichi Isaka has said that "speedy completion of the sale will lead to dispelling employees' concerns."

The store, located in Ikebukuro in Tokyo's Toshima Ward, will be closed for the day, according to Sogo & Seibu. The company has seen a decline in store numbers in recent years, with its 28 outlets nationwide in September 2009 now down to 10.

Union members had demanded that the parent company not force through the sale as a condition for calling off the strike.

The Japanese retail giant first announced the sale in November and planned to complete the transaction in February, but twice postponed the move as stakeholders, including the local government, signaled their disapproval.

The union is worried that the U.S. fund's plan to make its partner electrical appliances retailer Yodobashi Camera Co. a major tenant of the Seibu Ikebukuro store would force out current tenants and reduce its store space.

The store is a leading profit maker among the chain's major outlets, and concerns have mounted that if the plan goes ahead, the employees at the location could lose their jobs if sales subsequently fall due to the changes, the union said.

The labor union notified management on Monday that it would take industrial action after balloting its members in July.

According to industrial union UA Zensen, the last strike by a major department store union in Japan was held in 1962.

Strikes in Japan have been decreasing since hitting a peak in the mid-1970s.

The number of strikes lasting more than half a day has stood at 50 or less a year since 2009, making the planned strike a rare case, according to the Ministry of Health, Labor and Welfare.

Rarity of industrial action in the country led to surprise at the news from young shoppers in Ikebukuro. University students Mai Wakiya and Kyoko Kondo, both 19, said they were shocked industrial action was going ahead because they had "only read about strikes in textbooks before."

But they did not criticize the move itself. "It's the last resort for the workers who think they could lose their jobs. It's understandable they'd choose to strike," they said.