Can a wizard cast other spells with somatic components while concentrating on Bigby's Hand?

Question

I noticed a clause in Bigby's Hand that has me pondering...

The hand lasts for the spell's duration, and it moves at your command, mimicking the movements of your own hand.

Here is the situation:

Bob is a 9th-level wizard. He is carrying his Wand of the War Mage +2 in one hand, and his other hand is open. Bob does not have the War Caster feat.

Bob casts Bigby's Hand and uses it to grapple a foe.

Does Bob still have a "free hand" to cast a non-concentration spell the following round?

Bob doesn't want to drop the Wand, as it is his spellcasting focus and he wants the bonuses. He doesn't have the War Caster feat, so he cannot "perform the somatic components of spells even when [he has] weapons or a shield in one or both hands." But per the spell description, Bigby will mimic the spellcaster's hand movements. So if Bob makes "a forceful gesticulation or an intricate set of gestures" with his other hand, does that mess with the grapple?

I've never seen a DM rule that Bob was out of luck with somatic spells, but I'm looking at this from a RAW perspective.

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On the other hand, I can't help but picture the poor creature that's being grappled turned sideways while Bob puts his thumbs together to cast Burning Hands.

Answer 1

Yes.

The solution relies on the description that you quoted (emphasis mine):

The hand lasts for the spell's duration, and it moves at your command, mimicking the movements of your own hand.

Per my reading, this means that the Hand moves and mimics the gestures of the caster's hand when they command it to do so: during the casting of another spell, a caster is not commanding the Hand, hence the latter does not replicate the gestures of the caster.

Moreover, the description of the Grasping Hand says:

While the hand is grappling the target, you can use a bonus action to have the hand crush it.

and does not contain anything similar to "while the hand is grappling the target, one of your hands must be clenched".

Suppose that the Hand has been evocated in a previous turn: the caster's actions order may be the following:

• (BA) They move the Hand close to a creature, if neeeded. They mimic the gestures for grappling the enemy and perform the attack. In case of success, the implicit command is "keep on grappling", without requiring the caster's hand to be clenched.
• (A) Cast another spell with somatic components.

The "implicit command" reading is suggested by the Interposing Hand option:

Interposing Hand. The hand interposes itself between you and a creature you choose until you give the hand a different command. The hand moves to stay between you and the target, providing you with half cover against the target. [...]

The description explicitly states that the hand moves autonomously for interposing itself between the caster and the target, without requiring the latter to mimic the movements of the Hand. The "implicit command" is to adjust its position with respect to the target in order to defend the caster.

Answer 2

Most likely yes

Although that text says that the hand mimics the movements of your own hand, a later block of text says the following:

When you cast the spell and as a bonus action on your subsequent turns, you can move the hand up to 60 feet and then cause one of the following effects with it.

I would consider this to be specific text that overrides the previous general text. In order to make the hand do anything you need to make use of your bonus action.

On top of that, the spell descriptions says it mimics the movements of your hand. It doesn't say which hand. You could easily say that it is mimicing the movements of the hand containing the wand which is already in a perfect position for grasping something.