Slitherine

A square have 3 dice for shooting, but it's for all or is it for each side of the square?

It gets 3 dice and must split them if necessary.

May a square shoot after the unit took the option to from square in the assault phase?

You can shoot still if you formed square, but if started in square and tested to form tactical due to infantry assault, you can not shoot.
Also artillery attachment with square, you only can use it for one side of the square shooting, so if multiple assaults you only get the artillery die against one enemy.

deadtorius wrote:You can shoot still if you formed square,

I haven't got my rules with me, but I'm pretty sure this is not correct. The options for infantry charged by cavalry, while in tactical or extended line, are to form square or stand and shoot.
You cannot do both.

Cheers
Brett

hmm..right...p. 48 just under UNITS ALLOWED...

...must not have changed formation or retired as a reaction...

My mistake, was trying to go by memory and I did recall the not being allowed to shoot if you went from square to tactical as response to infantry charge. Most of the time if the Frog cav is lurking about I just form square so I don't,t have to deal with failed dice rolls, and shooting at them is no problem.

A square gets 3 dice (4 with artillery attachment) which must be split between all close range targets.
It cannot fire in the same phase that it formed square as a reaction to a cavalry charge.