Ten Directions Absolute Prison.
Copper walls and iron fortifications! From ancient times to the present, it has had a long and storied history. Established in antiquity, the prison made full use of the terrain and materials. Once inmates were locked inside, they could practically say goodbye to their freedom. They simply couldn't get out!
Back then, martial arts flourished, and skilled practitioners were numerous. But even the experts couldn't escape.
In modern times, the number of martial artists has dwindled. With the prison now reinforced using modern technological materials, who could possibly escape? A prison break? What a joke. The people inside could never get out, and those on the outside found it extremely difficult to infiltrate.
