From the website:
The Archer is a powerful figure as Archers possess the ability to inflict hits on the enemy army before they have a chance to strike back. Each Archer has First Strike (X), where X is the number of Battle Dice the Archer rolls before the first round of combat. Those Dice inflict hits as normal, then the Battle begins. Archers cost 2 koku each to deploy, and roll 1d6 for hits in combat. Each archer can absorb 1 hit.
After the initial hail of arrows and the armies collide, the Archer drops his bow and becomes essentially a Bushi, with the same stats as such. They do not however count as Bushi for Strategy Cards that check for Bushi.
Check it out here: http://www.l5r.com/products/board-game/
Personally....i see a MB's Shogun...