If you do wish to scout with Cavalry Archers, you need to place them in a block formation, which minimizes their archery abilities. If you leave the archers in a line, they tend to end up wheeling into trouble and getting mauled. The block formation is easier to maneuver and to make quick direction changes.
Cavalry Archers are the love them or hate them unit in Shogun: Total War. Many players find them to be the most invaluable unit in their army, while other don't even bother recruiting them. Either way the Cavalry Archer does have its advantages and disadvantages just like every other unit.
Cavalry Archer Vs Samurai Archer
The comparison is always made between these two units. Why use Cavalry Archers or vice versa. Well here are the differences.
Although this comparison may make the Cavalry Archer look pretty useless, they are not. The fact that they are one of the fastest units in the game adds a lot to there use.
The speed of the Cavalry Archer makes it ideal for scouting out the enemy. By taking a group of CA out ahead of the rest of your army you can get tactical knowledge of the enemy's position and troop makeup without having to move a slower unit in to do the job. Also, your scouting unit can get surprised especially if the conditions are foggy. Its much better if your Cavalry Archers round a corner to see a full 16 unit army right in their face because they can high-tail it out of there really fast, where as a foot soldier unit might get caught before it can run and you just lost a whole unit in the name of scouting.
If you wish to scout with Cavalry Archers, you need to place them in a block formation, which minimizes their archery abilities. If you leave the Cavalry Archers in a line, they tend to end up wheeling one end into trouble and getting mauled. The block formation is easier to maneuver and make quick direction changes (mike palmer).
Break Up Formations
One of the best and most popular uses of the Cavalry Archer is to break up an enemy army's formation. By running your Cavalry Archers at the flank of the enemy or even right at them, the enemy will have to peel off a unit or two to deal with you. This leaves holes in the enemy's main army formation that can be exploited by your main army. It also depletes the size of the enemy's main army. This works well if you are out numbered.
Had a number of times in which I persuaded enemy units stashed on a hill or half hidden in the forest to come running at my Cavalry Archers, which they couldn't reach of course due to their speed. In some instances the whole army was directed to face my (decoy) Cavalry Archers, and I could smash the weak flank with my real army, even uphill in a forest. Then, when Yari units are directed to my main assault, their Samurai Archers were easy prey for my Cavalry Archers' swords. Try not to attack them in a forest of course, and preferably from behind or flank (RagingPhoenix).
In the defensive role, Cavalry Archers make excellent 'teasers'. With my main defense on a hill back and the enemy on foot advancing I have my Cavalry Archers skirmish from the flanks. Inevitably, the enemy comes after you and lines up Archers to defend. This again peels away units from their main assault, which is still continued by the AI. So, you succeed in spreading the attack thin so not all of his army is coming at once (RagingPhoenix).
Run Them Down
With only the Yari Cavalry being faster, the Cavalry Archers are also a great choice to run down fleeing troops. When the battle seems won and the enemy Taisho is fleeing you need not just let them run to fight another day. Use your Cavalry Archers to attack them while they run. Although their hand-to-hand attack isn't that good, you receive a bonus for attacking from behind and charging and attacking a fleeing unit. So don't be afraid to attack those Yari units from behind when they are fleeing, you will be able to take them out. Even Yari Cavalry don't fight well when attacked from behind and running away.
The Cavalry Archers have other uses as well. One tactic supplied to us was on their use during bridge assaults.
I have found that Cavalry Archers are great for bridge assaults. You charge them across bridges and then to left or right, so as too avoid contact. Once set up they can harass the enemy from behind and the flanks. The enemy will peel off two units (Samurai Archers & Yari Samurai usually) to neutralize your Cavalry Archers. If you can get two Cavalry Archers and one Yari Cavalry across the bridge you can move the bulk of your force across the bridge and take very few losses. By running your Cavalry units away from the bridge once they are across, the enemy will have to follow and that will leave less of a force defending the actual bridge. If you can get two to three other units across the AI usually retreats. That is when your Yari Ashigaru or other foot soldiers can attack his exposed Samurai Archers and start a general rout (Clan Dragon).
Another use for Cavalry Archers is for missile unit hunting. I pretty much keep them in the wings firing their arrows, waiting for a unit of Samurai Archers or guns to stick its neck out. I'll then charge the Cavalry Archers in to hand-to-hand combat with them. They'll route the offending party in a heartbeat. Just make sure you're not getting suckered into a trap of Yari Ashigaru/Yari Samurai/Yari Cavalry, they'll make mincemeat of you before you can withdraw (Obake).
A note about deployment:
I find smallish units of say 25-40 Cavalry Archers used in close formation to be most useful. They present a small enough formation to remain mobile, can deploy into a line quickly, and can run down even a full strength unit of Samurai Archers under the right circumstances. Often such units represent army commanders (mike palmer).
Cavalry Archers also make great hit and run units. This is very simple, just run your unit right up to the enemy army and start launching some arrows. As soon as the enemy deploys a unit or two to go after you just run away. You can do this repeatedly by keeping your Cavalry Archer unit in skirmish mode. This is a great way to take out an enemy Taisho in battle, just hit and run his unit until eventually, he dies.
What To Watch Out For
Although we have pointed out some good uses for Cavalry Archers there are also some situations to watch out for and avoid.
Cavalry Archers are not the best hand-to-hand fighters on the battlefield. They can dispatch a unit of Samurai Archers or Gunners fairly quickly and easily, but beware of the Yari troops. When a lightly armored horse goes up against a tightly formed unit of standing Yari Ashigaru or Yari Samurai, the Cavalry tends to lose and lose very badly. So never take a frontal assault on standing organized Yari troops. If you must fight them in melee, try to defeat them by flanking them or attacking from behind.
Cavalry Archers are also the weakest of the 3 Cavalry units. So beware of Yari Cavalry and Heavy Cavalry. You stand somewhat of a chance against Yari Cavalry if you catch them off guard but the conditions have to be perfect so avoid attacking them at all in hand to hand. YC can are also the one unit that is faster than Cavalry Archers, so watch for their presence, because if they get too close it may be too late for you to do anything about it. As for heavy Cavalry, AVOID THEM. You cannot even come close to defeating this unit in hand to hand. You do have the same run speed so if you are ahead of them you can keep running and you won't be caught because the Heavy Cavalry tires faster than Cavalry Archers.
Your best bet against the units mentioned is to shoot them with arrows. They are all very susceptible to missile fire so that is your best bet.
Do not get into a shoot out with Samurai Archers. They have a longer range than you and are more accurate. Besides you're sitting on a horse, which is not a hard target to hit for a skilled samurai. So either charge the Samurai Archers in loose formation or back away and let another unit do it.
One last note about Cavalry Archers is that they are not as smart as we would like them to be. You can't send them across the map to scout and expect them to turn around when there is trouble. They need to be micro-managed a little more than most units do. They have a nasty habit of getting caught by a Yari unit in the flank when trying to turn around and run. So as a precaution, keep an eye on them.
Version 1.1 addition:
I love to use Cavalry Archers on Bridge defenses. This tactic really works when it's raining, and the Musketeer is of no use.
As my front line, I put my first wave of archers 3-5 units and
one Musketeer/Arquebusier. Behind them 2-3 other units. Aside from the couple of Naginata/YS/YA/Monks I have protecting them, I have 2-3 Cavalry Archers way far back. After the archers have worked their usual carnage & run out of ammo, I pull them farther back. Usually this encourages the enemy to charge more. Then, due their speed, I run the Cavalry archers
up from the rear and where there used to be just a Musketeer and/or melee troops, they have now have a fresh barrage of arrows coming in on them crossing the bridge and/or amassing a charge. Plus, the Cavalry Archers are either out of range of his remaining archers, or they don't have any more ammo either. Great way to put on a final rout.
Tactics provided by (from totalwar.com forum)
I did not directly quote some of the people mentioned above but their ideas were used in creating this document. Thank you to Everyone.