The french word <b><i>Flèche</i></b> means Arrow.
It relates more to the overall shape of the fortifications.
Like Andy said, they were open ended earthworks but I disagree with the fact they are pretty impregnable when it comes to NiR. At mêlée the modifier is -2 ( -3 if attacking from lower grounds), meaning that you could win the assault at 1:1 but with 1 chances out of 12 (not too good but still...). At 3:1, you have one chance out of two, etc...
With cavalry, the same rules apply <b>without the charge bonus</b>. Being open ended, once you win the hex you get no protection out of it; you are still exposed to ranged fire (and counter attack) so you may regret this kind of manoeuver.
Nevertheless, as far as I am concerned, I really like to try this stunning move when the opportunity comes. In a typical example, if you charge against the Northern Flèche with the whole VIII Corps Cavalry, you do it with 1087 horsemen (325 + 325 + (350 * 1.25) against 475 men (12 cannons and 175 infantrymen). The odds are 2:1 , meaning with the modifiers that you have 5 chances out of 12 to win. Not so good but when it succeeds, the effects on the ennemy's morale are often devastating. If I recall, I succeeded in doing it against Generalissimus Moss and he abandonned our game one or two turns after!!
[url="mailto:pyguinard@hotmail.com"]Lt Pierre-Yves Guinard[/url],
6e Division, II Corp
AdN