Quote Originally Posted by LegioXXXUlpiaVictrix
I can see a good way of using the checkerboard vs barbs: if the barbs swarm into the holes, push the principes forward a bit and compress the barbarians (against the men behind them), so they can't get enough room to swing their swords. If the barbs didn't swarm the holes, just switch between hastati and principes pushing forward/falling back in good order. The risk is of course that the entire line will be fighting at the same time at some points, and that the barbs will skirmish: threatening to enter the gap, then falling back, repeatedly, to tire the principes who would go backwards and forwards a lot (with heavier armor than the barbs wear).

But perhaps it's possible to counter this as well, by alternating between pushing the principes forward, then pushing them beyond the hastati, and the enemies in the gap would be compressed by a following (short) hastati advance. Or the principes/hastati formations could be deep enough to be able to present a deep enough front while still having men behind them move sideways into the gaps and hit the enemy flank harder than the enemy can hit the roman flanks.

In any case, by default the checkerboard doesn't give you any greater outflanking penalty than the opponent because where you are flanked, he is also flanked. Only if one side has equipment or training better suited to this kind of situation, would there be any difference. My guess is that the romans (and the samnites which they copied the checkerboard from) had made sure their equipment and training made them superior at this kind of fighting.

Anyway, I've had some fun experimenting with schemes of this type in EB

Good point there, Legio. I never thought about pushing the principes -forward- past the hastati. Hey, this could be an interesting perspective: See this. The principes and hastati push forward alternately as an offensive technique. The hastati engage, then if the principes come up and the enemy pause in confusion, then the principes take the initiative and take the offensive. And once the principes bog down, the now-rested or at least less-tired hastati move forward again and if the enemy pause, they take the offensive past the principes, who do not move back through the lines, but stay where they are to be the next second line, with the effect that the entire triplex acies moves forwards instead of backwards. The same attritional effect would apply.

Though of course this only occurs in situations where the opening presents itself, obviously, since sometimes the enemy is too strong for you to take other than the defensive. But we can see some potential of this applied to, say, Kynoskephalai and Pydna, where maniples -from the second line- would go to the attack into gaps in the phalanx when they went over uneven ground while the maniples in the first line would continue keeping them occupied.

Thoughts?