Counter-spelling and foci

[Taran]

Can you use your foci to counter-spell?

Is counter-spelling an offensive or defensive action?

[Mr. Death]

If you're counter-spelling someone's defenses, I'd say it's offense. If you're counterspelling someone's attack or maneuver, it's defense. I'd allow using the foci.

[Haru]

I would say yes on the foci, if they fit the spell you are countering.

Then it depends. A counterspell could be seen as an attack against the spell, and I would handle it like that if the caster wanted to break a thaumaturgy spell. On the other hand, especially when it comes to countering evocation maneuvers or blocks, I would match them. If someone puts up a defensive maneuver, countering it would be an offensive counterspell and vice versa.

Damn, Ninja'd 

[InFerrumVeritas]

I'd let foci counterspell as long as thematically appropriate.  Counterspelling comes up so little, I'm totally good with allowing it to be done with either offensive for defensive foci.

[Sanctaphrax]

Which element do y'all use for counterspelling?

[Haru]

The one that fits the spell that's supposed to be countered.
Spirit could work as a catch all, but I'm sort of against that. If you mainly use spirit for force effects, you can counter a force spell, surely. But a light spell? Sound? That's just not in your wheelhouse, and you should probably try a ritual if you want to counter a spell like that.

[narphoenix]

Which element do y'all use for counterspelling?

It depends on how you're counterspelling. I've had a Wizard use Water to Counterspell a Fire evocation. I could also see using Earth, for example, to Counterspell a lightning spell by changing the magnetic field in the area to make the lightning go in a circle.

[Taran]

I can see all kinds of combinations: 
Similar elements cancelling each other
Opposite elements
Water is the entropy element, so I'd allow water to counter-spell anything.