There was little practical difference as far as common hand-to-hand weapons and armour were concerned. A sword, as long as it is sufficiently sharp (and has a hard enough edge to remain so) and tough, will do its job. A spear, similarly. The basic methods for making swords and spears throughout East Asia and South-East Asia had many common elements; important functional features included differential hardening of edges and laminated construction. No country in the region had a monopoly on any essential method, and the Japanese were not lacking any essential method. The Japanese exported weapons to China and SE Asia during this time, so clearly their weapons were not considered grossly inferior. On the other hand, the Chinese were not impressed by the quality of these export weapons (which were often made as cheaply as possible).

Japanese armour would stop swords, spears, and arrows. Chinese armour would stop swords, spears, and arrows. Korean armour would stop swords, spears, and arrows. Given that the major users of armour in the region used armour that worked, there doesn't appear to be any major difference in quality of armour.

The Japanese invasion of Korea in the late 16th century (the Imjin War, 1592-1598) provides an opportunity for direct comparison. While there were some claims during the war that Japanese swords were better, the key Japanese advantage in hand-to-hand fighting was discipline and determination (both resulting at least in part from larger numbers of veteran soldiers with combat experience). As was explained to the King of Korea, "The Japanese are reputed to be good swordsmen, but it is possible for Koreans to draw swords and hold their ground. However, the Koreans seldom do this and merely run for their lives." (Annals of the Joseon Dynasty).

By this time (late 16th century), the key weapons on the battlefield were firearms. Here, there were important differences between countries. Until the mid-16th century, Japanese firearms lagged behind Chinese firearms. From the mid-16th century, European-style guns were enthusiastically adopted in Japan, and became the major weapon on the Japanese battlefield. Japanese musketry was a major factor in many of their victories in Korea during the Imjin War - the Korean armies (early in the war) deployed far fewer firearms than the Japanese, relying on the bow as their main personal ranged weapon. The Chinese, however, were much better equipped with firearms than the Korean armies, and deployed large numbers of cannons against the Japanese. The Chinese use of cannons was a major factor in their defeat of the Japanese at Pyongyang in February 1593 (however, one should not conclude too quickly that the Chinese victory meant that Chinese weapons were better - the Chinese/Korean force might have outnumbered the Japanese by 2 or more to 1). This pattern of Japanese muskets vs Chinese and Korean cannons was also important in the naval fighting (but superior Korean and Chinese seamanship, and better warship designs also mattered).

So, in summary:

• Major countries in the region were approximately equal in terms of technology for swords, spears, and armour.

• Until the mid-16th century, Japanese firearms were inferior to Chinese and Korean firearms.

• After the mid-16th century, Japanese handguns were superior, while Chinese and Korean cannons remained better.

Near the end of the Ming Dynasty, the Chinese evaluated various muskets (including European, Ottoman, and Japanese weapons). From their trials, they decided that the Ottoman guns were best, and planned to adopt similar weapons for their armies. At the core of this modernisation program was the recognition that Japanese guns were better than the Ming guns in use.

The Japanese bow (yumi) was optimised for short range shooting, using heavy arrows in an attempt to penetrate armour. Korean and Chinese bows were longer ranged, but would have been less effective against armour at short range. (The Manchus also used bows designed to shoot heavy arrows at short range, and their bow became the standard Chinese military bow after their conquest of China in the mid-17th century.) Chinese and Korean crossbow technology was well-developed, while the crossbow was largely absent in Japan. These differences in bow/crossbow technology don't appear to have been of battle-winning importance during the Mongol invasions of Japan, and weren't of battle-winning importance during the Imjin War (by which time the musket was the key Japanese weapon and the bow had been relegated to a secondary role).

• China and Korea used a broader range of bow and crossbow technologies, which could be considered superior. This difference did not translate into a war-winning advantage.

As already briefly mentioned above,

• Japanese warships were inferior to Chinese and Korean warships.