PL stands for Patrol vessel Large, and the class is named after Mount Aso, the largest active volcano in Japan.

Having Bofors 40 mm L/70 autocannon with fire-control system, this class is safely able to deal with heavily armed spy boats of DPRK which intrude into Japanese waters.

In the back of the bridge's side, this class has display devices that can be used to instruct other ships to stop even at nighttime.

And on the bridge superstructure, this class is equipped with the LIDAR system to acquire targets with high accuracy.

The TT-1500 will have a maximum speed of 24 knots, considerably slower than the original Aso, however it is projected to have a better low-speed stability hence making it better for low-intensity patrol and search-and-rescue missions.