"They make ships larger than ours, about 2,000 tonnes in size ... The lower part is made of three decks, so as to better resist storms, which occur frequently. These ships are separated into several compartments, so that if one is touched during a storm, the others remain intact."
— Niccolo da Conti, 15th century Italian traveller to the Far East
A three-masted menace on the high seas, the War Junk distinguishes itself over the normal roundship-type vessel with two aspects: firstly, like all Asian warships, it has an immense wood cost which is only offset by its low metal cost. Next, it is also faster and hits harder, making it a more efficient heavy ship, if compared at least to the less advanced roundships of the west. In fact, the War Junk is more akin to a cog than a roundship, despite its seeming resemblance to the roundships of Mediterranean nations, and in the Castle Age could easily macerate most Western navies and even castles are not safe from the raking fire of the War Junk's fire lance-toting marines. The only problem for China would be how to shell out sufficient timber to meet the demand for these vessels — Japan need not worry greatly as the metal saved on these ships would be put to good use in the form of Bushi infantry.
Unlike the North Sea, Baltic or the Mediterranean, the extensive coastline and the hazards of the Pacific Ocean required vessels that were large and solid enough to survive the highly turbulent waters of Asia. As such, large ships were often more of the norm than the exception especially in north Asian navies. Chinese vessels of the mediaeval era contained many innovations, such as stern-mounted rudders and bulkheads which provided greater mobility and durability, which increased chances of survival in combat against storms and enemy fleets alike.