Daiichi Undo Park, Public sports park in Zushi, Japan

Daiichi Undo Park is a district park in Ikego 1-chome, Zushi, built on land returned from the Ikego ammunition depot in 1972. It covers the third-largest area among Zushi's parks and was redeveloped in the early 2010s. Facilities include a natural-turf baseball ground whose backstop stand doubles as a helipad in emergencies, tennis courts, a kyudo hall, an archery range, and outdoor pools open from July 1 to September 15.

The park occupies part of the Ikego ammunition depot, returned in 1972 after a citizens' campaign in 1967. A Keikyu 600 series car, DeHa 601, was donated by Keikyu in 1984 and stands outdoors; it is not open for entry. A preservation group formed in 2014 to maintain it.

Each autumn the whole park hosts the Zushi Citizens' Festival, a city-wide event held on its grounds. The park's name is a curiosity: there is no "Second" athletic park in Zushi, and none is planned. The Keikyu DeHa 601 car is kept by a preservation group formed in 2014.

The grounds are open from early morning through the evening with parking for approximately 110 vehicles. Parking fees start from 100 yen for the first hour.

The park features separate pool areas with varying depths, including a current pool and a 25-meter swimming pool. These specialized facilities open during summer months and provide different swimming experiences.