Artillery
I will have to add harquebusiers (shooters) to each of the northeastern asian nations. These countries have been using these weapons in various wars dating back to the 16th century.
For Artillery, China will have cannons; Flamethrowers which will be available on a certain ship and Hwacha cannons that shoot automatic volleys. The hand cannon (fireworks thingy) will be also of use. Their navy includes only Battleships and normal ships.
Japan will have only cannons and giant crossbows as their artillery. For navy, they can hire pirates or make their own ships.
Korea will have 2 types of cannons, Hyeonja and Hwangja, the latter being more accurate but less in range. They will also have a more advance Hwacha. Their navy will include battle ships, Turtle Ships, and the more common Panokseon.
I have also decided to add a new nation: Manchuria. This country (sometimes called North China) has had relations with China, Japan, Korea and Russia. The said countries have been waging wars in Manchuria to decide who can control it.
These countries fought wars that could parallel the European wars. I hope to achieve that goal.