On the last fourm I was on(armchair General) we had a big 50 page argument about this
it may be impossible for them to actively invade each-others homelands, but what about fighting a proxy war or even expeditionary forces fighting in eastern parthia/central asia.
Now, about the question of how well armored Han troops were, the han chinese metgeruical(sorry about the spelling) technology was equal to or better than the romans, but there focus was not on heavy infantry, as were the romans, but towards Calvary to fight on the plains against the steppe nomads which were the Han Chinese's only major threat.
The chinese army was remarkably balanced for a ancient army between missile troops, heavy infantry, and Calvary with shock and missile Calvary.
While Roman armies had a heavy emphasis on shock. The main building block of the roman army was the legion, witch is basically a heavily armored killing machine that is ment to be moving
Forward. Though one of the great strengths of Roman armies(notice not legions) was the auxilia system. Instead of dividing their resources to create many different kinds of troops, they could specialize on the heavy infantry miles, while client kingdoms could focus on providing auxilia that specialized on one certain type of warfare that the client kingdom was already proficient in.
This meant that instead of having to train or equip different kinds of troops, they could just recruit/hire a group of nearly fully trained warriors that are extremely proficient in their field of warfare.
For example, while the chinese trained their people at crossbows, which is much more exepenive than a bow and is less useful in anicent warfare
Also, the romans had superior logistics and enginneering than the chinese. Things like regularly building camps with advanced infrastructure, the fortifications, roads, and bridges the legion built, their advanced ability to cross rivers(Caesers bridge across the rhine for example), and their ability at siege warfare which brings me to my next point, Artillery.
Chinese artillery seems to be very anti-personnel, like the peace that shoot 100 arrows at a time and a heavy utilization of a type of ballista that is just a giant sized up crossbow instead of the more advanced roman designs using coils of rope or hair. Along with tention trebuchets, thats probbley what a chinese expidtionary force would carry along.
Now, the romans seem to have a greater focus on anti-fortification artillery, though they did have something called the Scorpio which is comparable to some of the chinese inventions. Also, the romans had advanced ballistas and even repeating Ballistas. In addition to this the romans had the oranger, which is a catapult which uses the same torison system that the Scorpio and Ballistas used.
Also, the romans knowledge of engineering is exhibited particularly during sieges, like how they had very advanced sapping techniques, built siege towers and combined them with rams and Ballistas to form a kind of primitive tank, also the romans built extensive siege works (look up the
Siege of Alesia)
Also, the romans had better tactical leadership with their centurions(the equivalent of junior officers and senior NCOs combined) and Princepales(basically mid to low level NCOs). Just to be a Centurion, you had to be in the legion on active duty in combat for at least a decade. After that you had the tribunes which were young officers from the senate which mostly proformed administrative duties, but never the less still had tactical command, though mostly that was left to the senior centurions. Most Tribunes served their time in the legion and then left for civilian life but a few stayed on and were eventually promoted. The commander of the legion was the Legatus Legionis. He was mostly a experienced tribune that was eventually promoted, though it is not unusual to have a Legatus that was promoted through the ranks, particularly from the Calvary.
Opposed to the romans system of command, the basic chinese unit was a 50 man unit lead by a junior atristocratic chinese officer with a unit of 300 lead by another officer roughly comparable to a major, then you had a commander of 3,000, which is roughly compareable to a senior Colonel or a brigadier general and after that you had generals of 10,000.
Also, the romans had one big thing going for them.
They were some of the most determined and persistent Sons a B*tches in the ancient world Even if they got curb-stomped in their first few clashes with the enemy, they would try to adapt and just keep coming at their foes till they were completely destroyed. (Punic wars for example)
Basic breakdown
If the battle was on an open ground, even to slight advantage to the chinese army, espeically if the chinese could keep the roman army on the move and not let it fortify the chinese have a pretty decent shot at defeating the roman army
If it was on Mountainous/hilly/rocky or otherwise constricting terrain slight to moderate advantage to the romans. But if the romans could dig in in this type of terrain, the chinese will have a severe disadvantage
Though alot of what would happen in the battle would depend on the generals involved
But if its a seige, especially if the romans are besieging, the romans advantages in engineering and siege technology will nullify any chinese advantages in generalship and Calvary, though there missile troops might be good, but once the heavily armored roman legionaries break though the walls and move into the narrow interior of the fort/settlement, all bets are off for the chinese.
Allthough again, in a pitched battle, Generalship and the quality of commanders will be a huge factor
In the big picture though, the chinese may win the battle, but the romans will win the war though their methodical style of warfare
But the rome would not be able to get to china proper, and the chinese may try to adapt to the roman style of fight then who knows what could happen or maybe they could say it was a failed expedition in a far off land and eventually codify the event and then let it fade into history
That was an epic post
-Ace_General-