How do foci and somatic+material components interact when it comes to occupying a hand?

Question

In 5e, the rules state the following regarding spells with somatic and material components:

Somatic (S)

Spellcasting gestures might include a forceful gesticulation or an intricate set of gestures. If a spell requires a somatic component, the caster must have free use of at least one hand to perform these gestures.

Material (M)

Casting some spells requires particular objects, specified in parentheses in the component entry. A character can use a component pouch or a spellcasting focus (found in chapter 5) in place of the components specified for a spell. But if a cost is indicated for a component, a character must have that specific component before he or she can cast the spell.

If a spell states that a material component is consumed by the spell, the caster must provide this component for each casting of the spell.

A spellcaster must have a hand free to access these components, but it can be the same hand that he or she uses to perform somatic components.

(5e Basic rules, p.79)

Now, I take this to mean that a hand holding a focus is considered free for the purpose of Somatic components, as the focus is serving as a replacement for the 'normal' components and the rule is in place that material & somatic components can use the same hand. I also assume this still applies even if the focus is a shield with a holy symbol inscribed on it, as is the case for Clerics and Paladins:

Holy Symbol.

A holy symbol is a representation of a god or pantheon. It might be an amulet depicting a symbol representing a deity, the same symbol carefully engraved or inlaid as an emblem on a shield, or a tiny box holding a fragment of a sacred relic. The Player’s Handbook lists many gods in the multiverse and their typical symbols. A cleric or paladin can use a holy symbol as a spellcasting focus, as described in chapter 10. To use the symbol in this way, the caster must hold it in hand, wear it visibly, or bear it on a shield.

(5e Basic rules, p.49)

However, I'm not 100% certain about that; The War Caster feat in the PHB (p.170) has a benefit of being able to perform the somatic components of spells even when you have weapons or a shield in one or both hands, and that's giving me a bit of doubt as to whether or not you can use a Holy Symbol shield to perform somatic components. That may be there just for if a non-Divine caster obtained a shield proficiency or if a divine caster was casting a no-material-component spell, however.

So, the question:

When using a focus or a component pouch, does the focus remove the requirement of the (uncosted) material components, or is the focus now the (sole) material component?

If the latter is true, then the rule of "A spellcaster must have a hand free to access these [material] components, but it can be the same hand that he or she uses to perform somatic components." extends to the focus, because it's no different from the material components that the spell normally specifies. It's literally just taking the place of the normal material components as a different material component. If it's the former, then the focus is an object that removes the need for material components, but it occupies a hand that cannot be used for somatic components as it itself is not a material component.

Given the specifc phrasing of the ruling of "A character can use a component pouch or a spellcasting focus (found in chapter 5) in place of the components specified for a spell.", I'm inclined to believe that the latter is true and the focus is acting as the material component in place of the normal components, but I am not sure.

Answer 1

According to lead rules designer Jeremy Crawford:

The intent is that the shield hand can be used for a somatic component if the holy shield is used to cast the spell.

In a tweet exchange on 21-23 November 2014, @Sword_of_Spirit asked:

@JeremyECrawford Holy symbol engraved shield counts as material component, but does holding the shield replace somatic component also?

Crawford replied:

@Sword_of_Spirit The intent is that the shield hand can be used for a somatic component if the holy shield is used to cast the spell.

And further clarified that the shield arm cannot be restrained:

@Sword_of_Spirit You still need use of the shield arm to move it while performing the somatic component.

Answer 2

Can a Cleric/Paladin use a hand carrying a Holy Symbol Shield to perform somatic components?

Based on the information you have quoted, yes. As the shield is a holy symbol, holy symbols act as a focus, the focus substitutes for the material component, and a hand holding a focus can perform somatic components.

I'm not exactly sure what your second question is. If it is:

Can an arcane class with shield proficiency use a focus in one hand, a shield in the other, and still perform somatic gestures with the focus hand?

Then I would yet again say, that based on what you have quoted, yes. The shield is in one hand, and the focus in the other. The focus substitutes for the material components, and the hand holding the focus can perform the somatic component.

Update: As another answer points out, the designers recently gave a clarification that would seem to support this logic.

A divine focus can be emblazoned on a cleric’s shield, enabling the cleric to wield a weapon in the other hand and still cast spells. A wizard can hold an arcane focus in one hand and a weapon in another and still cast spells. A druid must hold mistletoe as an arcane focus, so druids must either stash their shield or their weapon to cast.

http://dmdavid.com/tag/9-more-fifth-edition-dd-rules-questions-answered-by-the-designers/

Answer 3

Errata to the Player's Handbook has explicitly clarified that the rule allowing for holding material components in the same hand as is used for somatic components extends to foci used in place of the standard material components:

Spellcasting

Material (M) (p. 203). The final paragraph now reads as follows: “A spellcaster must have a hand free to access a spell’s material components—or to hold a spellcasting focus—but it can be the same hand that he or she uses to perform somatic components.”

[2017 PHB Errata]

Answer 4

You still need a hand free for the somatic component, but it’s not usually a problem.

Here are the general rules for somatic and material components (BD&D p. 79):

If a spell requires a somatic component, the caster must have free use of at least one hand to perform these gestures.

A character can use a component pouch or a spellcasting focus (found in chapter 5) in place of the components specified for a spell. . . . A spellcaster must have a hand free to access these components, but it can be the same hand that he or she uses to perform somatic components.

You don’t generally need to carry your spellcasting focus in hand. You just need a free hand to use it while casting spells that require it. This makes perfect sense when you consider the nature of most spellcasting focuses. Crystals, orbs, and sprigs are small items that you can keep in a pouch or pocket like any other material component. Rods and wands are specifically designed for quick handling and gesturing. Staves are no longer strictly two-handed.

Somatic components only become a problem when using holy symbols, which allow you to wear them instead of touching them. Here’s the specific rule (BD&D p. 49):

To use the symbol in this way, the caster must hold it in hand, wear it visibly, or bear it on a shield.

This means that you can easily get in a situation where you do not have a hand free for a somatic component. Note that bearing a holy symbol on a shield means attaching the symbol to the face of the shield. The specific rule allows you to do this and still use the symbol as a spellcasting focus, even though you are not touching it as generally required. However, if you also wield a weapon, then you will not have a hand free for somatic components.

Answer 5

Does the rule stating that you can use the same hand for material and somatic spell components extend to objects which replace the need for material components such as foci?

No, RAW, there is nothing which says that Foci can be held in the hand used for somatic gestures.

If I were an arcane class that obtained a shield proficiency, could I have a shield and focus and cast spells with somatic and material components perfectly fine with no equipment juggling?

No, however the equipment juggling is not as difficult as you might think. As part of your action, you may use the focus for your material components and then afterwards put the foci away, thus doing the somatic gestures with an empty hand. On your next turn, you may use your empty hand for the somatic gestures, and then grab your foci and use it for the material components. What this does cost you however is the ability to cast a spell which requires both somatic and material components as a reaction.

If I'm a cleric with a shield serving as a holy symbol & mace, am I perfectly fine casting spells without having to stow my weapon?

No, you will need to stow your weapon as part of your free action, thus losing your weapon for reactions during your turn.

In general, you can use your empty somatic hand to get components, but you can't use your filled focus hand to do somatic gestures.

This is one of the purposes of the warcaster feet. It allows you to find in melee and cast spells to full effectiveness. This is also one of the reasons why the quaterstaff was turned into a versatle weapon, so that Wizards could hold the staff in one hand while using the other for somatic gestures.

This may seem to make foci items to be an extra cost to spell casting over the component pouch, and in a way it does. The reason for this, is that foci often will have other magical properties. Foci that function as other items, such as a magic wand, or a shield with a holy symbol should be seen as a means to enhance the "realism" of the story, by allowing you to not worry about collecting various material components and worrying about how to keep track of that. Instead, you may have your foci.

These rules also prevent a spellcaster from using two foci at once, or being able to both spell casting and melee fighting unless it comes as a class feature or feat, just as a martial character needs to choose between doing ranged or melee tactics, but not both without a reduced cost in damage.

It's advised that you don't worry about these details too much unless they are causing some clear imbalance in your game however. The rules are there to clarify how these things work, not to restrict reasonable actions.