Project Description

A 35,000-capacity baseball stadium with the world’s largest retractable roof and a natural grass field, located in a bitterly cold and snowy region in Japan. The 167m span retractable roof and a 70m high freestanding glazed wall are designed to both grow the natural grass and provide a shield from the harsh environment. The retractable roof moves 132m horizontally on reinforced concrete track-girders by 24 motorized bogies. Its three-hinge trusses allow the roof to run smoothly on the track-girders and accommodate thermal movements.

Judge’s comments

This fantastic stadium is a demonstration of bold structural engineering that responds admirably to the brief and the surroundings.

This stadium has two large-scale roofs; a large seismic isolated fixed roof covering the stands and the world’s largest retractable roof covering the field. An innovative sliding construction method was utilised for the roofs based on structural analysis.

Additionally, a glass wall structure located on the southeast of the stadium is designed with thin steel frames to allow for sunlight to promote the growth of natural grass. Parametric design and structural optimisation were conducted to determine the structure shape and maximise transparency while satisfying the structural performance.

Project overview

Structural Designer

  • Obayashi Corporation

Client Name

  • Fighters Sports & Entertainment Co. Ltd.


  • Hokkaido, Japan


  • Obayashi Corporation, HKS Inc.

Principal Contractor

  • Obayashi Corporation

Key Contractors

  • Yamashita PMC Inc. (Project Manager, Construction Manager)

    Iwata Chizaki Inc. (Contractor) - JV Constituent Company

Year Submitted

  • 2023

Key attributes

  • Process