Supreme Court, Third Petty Bench · September 14, 2026 · Reiwa 5 (2023) (A) No. 395 · Decision; final appeals dismissed

Bid coordination among four designated contractors for new underground Shinkansen terminal stations was held to substantially restrain competition, because each of the four was realistically able to supply the work.

Violation of the Act on Prohibition of Private Monopolization and Maintenance of Fair Trade (criminal)

Facts

Executives of four major general contractors were charged with unreasonable restraint of trade. The client designated the four companies and ordered, one after another by competitive quotation, the construction of new underground terminal stations for a Shinkansen line. The executives were found to have agreed on which company would win each order and to quote prices that would let that company win, and to have exchanged information such as quotation prices. Two of the companies and their executives appealed.

Issue

The appellants argued that the works were of unprecedented difficulty, that the companies able to carry them out were in practice limited, and that there was no competition to begin with. The question was whether the conduct "substantially restrains competition in a particular field of trade".

Ruling

The Court found that the grounds of appeal did not fall under article 405 of the Code of Criminal Procedure, and then ruled on the point of its own motion. In deciding whether competition is substantially restrained, it is appropriate first to examine, on the basis of the nature of the works and objective facts about each company's capacity, whether supply was realistically possible. The four companies had advanced technology and resources and track records in works with similar or common features, and the Court found that each was realistically able to supply. Exchanging information in that situation created a state in which the winner and the price could be controlled to some extent, which is a substantial restraint of competition; the judgment below was upheld in its conclusion. There is a concurring opinion. In outline, it states that objective facts about supply capacity should be examined first and that the subjective circumstances of those involved are not decisive.

Provisions

Antimonopoly Act, arts. 2(6), 3, 89(1)(i), 95