The Odate Dome (Sea of Trees) is one of the world's largest wooden domes, located in Odate City, Akita Prefecture. This is the hometown of the faithful dog Hachiko. Its size is as long as 178m along the major axis, 157m along the minor axis, and it is 52m high. It surpasses the greatest local dome, the Izumo Dome (diameter of 140.7m, height of 48.9m), the Tacoma Dome in Washington state (160m along the major axis), and a dome-shaped gym of Michigan State University (162m in diameter). It can therefore compete with the other largest domes of the world.

The Odate Dome was designed by Toyo Ito & Associates, and was built by Takenaka Corporation. About 25,000 glued laminated planks of Aita Japanese cedar wood (more than 60 years old and more than 20cm in diameter) from the northern prefecture were used.The supply system of wood in Japan has evolved with the times. The time needed for harvesting and processing structural timber which is used to build the dome is shortened and so is the transportation distance and the time needed for transportation. This has reduced the environmental burden caused by the transportation process.

The shape of the dome's roof is like an egg that corresponds to the track of a baseball. It minimizes the resistance caused by the monsoon in winter and it maximizes natural ventilation, (caused by both the wind and temperature differences) in summer. An 8% permeable Teflon film (double compound formation) is used for the entire roof. A lighting strength of 1,000 to 1,200 lux is assured throughout the year. This reduces the amount of electricity needed for lighting and creates a bright and healthy space.

It is not only used as a multipurpose arena for baseball, soccer, track, field tennis and others, but also as an event site.