Does a monk get martial arts die damage on improvised thrown monk weapons?

Question

The monk's martial arts ability states:

Your practice of Martial Arts gives you mastery of Combat styles that use unarmed strikes and monk Weapons, which are shortswords and any simple Melee Weapons that don't have the Two-Handed or heavy property.

I am specifically asking about a shortsword, which is a monk weapon by definition, but this question could apply to any monk weapon that does not have the thrown property.

The monk's martial arts ability also states:

You gain the following benefits while you are unarmed or wielding only monk Weapons and you aren't wearing armor or wielding a Shield... • You can roll a d4 in place of the normal damage of your Unarmed Strike or monk weapon.

I would be more comfortable if this said "You can roll the Martial Arts Damage Die shown in the Monk Level / Ability Progression Table" rather than "you can roll a d4", but the other questions I looked at in researching this took that as an assumption and no one challenged them, so...(Note: Rykara pointed out that the rules actually do indicate the table is to be used. Unfortunately the online source I was citing did not have that line from the PHB)

The rules for using an improvised weapon state...

If a character uses a ranged weapon to make a melee Attack, or throws a melee weapon that does not have the thrown property, it also deals 1d4 damage.

The rules for using an improvised weapon also state...

At the DM’s option, a character proficient with a weapon can use a similar object as if it were that weapon and use his or her proficiency bonus.

Unfortunately, that and the Tavern Brawler feat are as close as we get in RAW to saying that "If you use an improvised weapon to make an attack, you normally don't get to add your proficiency bonus to the attack." I think we can take it as well-accepted although not explicitly stated that using a melee weapon without the thrown property to make a thrown attack does not count as an attack with a weapon with which you are proficient.

Consider a monk wielding a shortsword and fitting all other requirements for using the martial arts ability.

The shortsword is a melee weapon that does not have the thrown property and has a base damage of d6.

If the monk throws the shortsword it would become an improvised weapon, and thus normally would deal d4 damage.

However, in this case does specific beat general and allow the monk to replace the d4 "normal damage" of an improvised monk weapon with the martial arts die damage, which would be d6 at 5th level?

Or, does the fact that the monk is throwing the shortsword as an improvised weapon disqualify it from being considered a monk weapon, in the same way that one cannot use proficiency for an improvised weapon attack because throwing a melee weapon without the thrown property is no longer a weapon with which one is proficient, and thus remove the ability to use the martial arts feature?

This question: Does Martial Arts Damage Apply to Ranged Attacks with Monk Weapons? affirms that monks get their martial arts die damage on ranged weapons, but the question only considers melee weapons that already possess the ranged property, not improvised weapons.

This question: Does using versatile weapons with 2 hands disqualify them as Monk weapons? affirms that monks get to use their martial arts feature on all monk weapons, even when they use them in ways that would disqualify them from being monk weapons (in this case, using a versatile weapon two-handed).

Related: Are weapons with the "Thrown" property considered a "Ranged Weapon" for the purpose of sharpshooter?

Somewhat related: Does a Monk's Martial Arts die replace all of a magic weapon's damage, or only the die portion of it?

Answer 1

Replacing improvised weapon's 1d4 with Martial Arts

While the damage die for monk weapons (and unarmed strikes) starts out as a d4, which also happens to be the die used for improvised weapons, this does not mean that a monk can treat improvised weapons as monk weapons.

The full description of damage for monk weapons makes it pretty clear that the "d4" is just the lowest level of the scaling die as indicated on the leveling table because it goes on to say (though you don't cite it):

You can roll a d4 in place of the normal damage of your Unarmed Strike or monk weapon. This die changes as you gain monk levels, as shown in the Martial Arts column of the Monk table.

You have it backwards: monk weapons use a d4 (that scales) because they are monk weapons. They are not monk weapons because they use a d4 (that scales).

---

Improvised weapons vs Monk weapons

Improvised weapons are not included in the list of weapons that may be treated as monk weapons. If a monk throws a monk weapon that lacks the thrown property, it is considered an improvised weapon which deals d4 damage (which is, coincidentally, the same die as the lowest level martial arts die).

Under the section header for improvised weapons, we see:

If a character uses a ranged weapon to make a melee attack, or throws a melee weapon that does not have the thrown property, it also deals 1d4 damage.

You express some misgivings about interpreting this to mean that such a weapon would be considered an improvised weapon because the rules say "it also deals 1d4 damage" instead of "it is also considered an improvised weapon."

The fact that this info appears under the section for improvised weapons and not the section about weapons in general makes it clear that the d4 damage die is the result of the weapon's improvised usage. It also serves to inform us that the attacker, in addition to not benefiting from their proficiency bonus, uses a d4 instead of whatever the weapon's die (or martial arts die, in the case of a monk) would normally be.

---

A note on your second related question

To clarify/correct your remark on the second related question where you say that the question/answer:

affirms that monks get to use their martial arts feature on all monk weapons, even when they use them in ways that would disqualify them from being monk weapons

A versatile weapon wielded with two hands is not a two-handed weapon from the standpoint of the rules and therefore qualifies as a monk weapon regardless of how many hands are used to wield it.

Weapon types (1H, 2H, versatile) dictate how they may be wielded, not the other way around. That is, using a versatile weapon with two hands does not make it a 2H weapon any more than wielding a glaive with 1H makes the glaive a 1H weapon.

---

So to bring it all together

If a monk throws a monk weapon that lacks the thrown property (and is not deemed ergonomically identical to a monk weapon that does possess the thrown feature†), it is considered an improvised weapon and the attack does not benefit from the monk's proficiency bonus and deals 1d4+stength modifier damage (period).

Martial arts does not apply to the d4 of this ranged weapon attack because martial arts can't apply to improvised weapons.

For completeness, if the monk were to take the Tavern brawler feat, which grants the character proficiency with improvised weapons, the monk would be able to add her proficiency bonus to the attack but not her martial arts. It would still be an unscalable 1d4 because proficiency and status as a monk weapon are independent things.

†^{I'm not sure what weapon could be considered similar to a monk weapon only when thrown. Perhaps a shuriken? You can't really stab with a shuriken like you could with a dagger but they might be thrown similarly, depending on the size/design.}

Answer 2

Short answer: DM discretion

Improvised Weapons in use

Technically, improvised weapons are something that the DM could give proficiency to on a case-by-case basis, like a table leg acting as a club. But in this example, a shortsword is typically meant to be used as a close-up weapon, not a thrown weapon.

Tavern Brawler

With the Tavern Brawler feat, you are automatically proficient with all improvised weapons, which in a way also covers improvised weapon use like boomeranging your sword to an opponent of 15 feet away.

Discretion and ammunition

So in the end it's more up to the DM's discretion on this case. Personally, I think throwing a dart while one-handing a sword is definitely within a monk's combat ability. And really, the damage can be comparable right at level 5 when the monk die increases to 1d6 for unarmed strikes and monk weapons. It just becomes what is the ammunition.

How I would rule it

In my case, I would remember how often the monk uses thrown/range weapons, and if they do so fairly often, I would allow it but if they are typically more up close and punchy, I wouldn't allow it. But I could still bend around it, following the rule of cool in, say, a last-ditch attempt to prevent the monk's backstory Big Bad from escaping.

Answer 3

Two different replacement effects

Can a shortsword can be both a monk weapon and an improvised weapon at the same time? Rykara argues that it cannot, that when it becomes an improvised weapon it ceases to be a monk weapon. The rest of their answer follows logically from that assumption.

While certainly plausible, there is no clear textual evidence that a monk weapon cannot be an improvised weapon, or an improvised weapon cannot be a monk weapon. It is clear that a weapon is either a Simple Weapon or a Martial Weapon - those categories are mutually exclusive. Also mutually exclusive are the categories Melee and Ranged - a weapon cannot simultaneously be both of these.

The definition of a monk weapon, on the other hand, shows that it is not exclusive to the other categories:

monk weapons, which are shortswords and any simple melee weapons that don’t have the two-handed or heavy property.

A shortsword is both a monk weapon AND a Martial Melee weapon. A handaxe is both a monk weapon AND a Simple Melee weapon. Classifying something as a monk weapon does not exclude or remove its other classifications, it simply adds to them.

Similarly, the definition of a improvised weapon does not exclude or remove other categories: (emphasis mine)

An improvised weapon includes any object you can wield in one or two hands...If a character...throws a melee weapon that does not have the thrown property, it also deals 1d4 damage. An improvised thrown weapon has a normal range of 20 feet and a long range of 60 feet.

Throwing a shortsword includes it as an improvised weapon; it does not exclude it from being a monk weapon any more than it excludes it from being a martial weapon or a melee weapon.

Further evidence that the categories "monk weapon" and "improvised weapon" are not mutually exclusive comes from the monk's ability to deflect missiles (full text below). Using that ability, a monk can catch and throw back weapons at attackers, whereupon they become monk weapons. Since some of these weapons otherwise fit the definition of improvised (a monk catching and throwing ammunition, for example, or returning a melee weapon that was thrown at them), this shows that a weapon can be both a monk weapon and an improvised weapon simultaneously - although in this case it is a monk weapon because the monk's ability explicitly makes it so rather than because it meets the definition of a monk weapon.

So if you accept, as I do, that a thrown shortsword is still a monk weapon, or at least can be treated as such, what happens then? Unfortunately, we then have two rules that both apply to replacing the damage and their results are often mutually exclusive.

As an improvised weapon, the thrown shortsword is subject to:

If a character...throws a melee weapon that does not have the thrown property, it also deals 1d4 damage.

But as a monk weapon, the monk:

...can roll a d4 in place of the normal damage of your unarmed strike or monk weapon. This die changes as you gain monk levels, as shown in the Martial Arts column of the Monk table.

While the improvised replacement effect replaces any damage that the weapon does, the monk replacement effect replaces only 'normal damage'. Here we are left to wonder what is 'normal' damage. Since this is not a game term, we have to consider the standard English meaning.

This could mean the 'the damage the weapon otherwise does, whatever that is' - in which case, the improvised weapon replacement effect would first replace the weapon's damage with a d4, and then the monk replacement effect would replace that d4 with the martial arts damage die.

Or, 'normal' could mean only 'the defined damage for that weapon' - in which case, the improvised weapon replacement effect would first replace the weapon's damage with a d4, and then the monk replacement effect could not do anything because the weapon was no longer generating 'normal damage'.

Unfortunately we have no way of distinguishing between the two. Thus, it is the DM's call as to which replacement effect, improvised weapon or martial arts, to use. A DM should feel justified in whatever decision they make on this matter.

Context Matters

Let's be clear on what we don't want: we don't want the monk to be able to take any melee weapon (monk weapon or not) and throw it at any point for a martial arts damage die.

Even allowing the martial arts damage die to a thrown weapon is a considerable bump to monk ranged damage capability, since normally that damage boost would only be allowed on melee attacks.

On the other hand, we have to admit that the monk can already get a martial arts damage die to improvised weapons, and even ones that are not monk weapons, by using their deflect missiles ability. Suppose someone had thrown the shortsword as an improvised weapon at the monk. Then, the monk would be allowed to use their deflect missiles ability to attempt to catch the shortsword and throw it back - with success earning them the right to do damage as a monk weapon - but they would have to spend a ki point to do so (emphases mine):

Starting at 3rd level, you can use your reaction to deflect or catch the missile when you are hit by a ranged weapon attack. When you do so, the damage you take from the attack is reduced by 1d10 + your Dexterity modifier + your monk level. If you reduce the damage to 0, you can catch the missile if it is small enough for you to hold in one hand and you have at least one hand free. If you catch a missile in this way, you can spend 1 ki point to make a ranged attack with the weapon or piece of ammunition you just caught, as part of the same reaction. [Errata: The range of the monk’s ranged attack is 20/60 feet.] You make this attack with proficiency, regardless of your weapon proficiencies, and the missile counts as a monk weapon for the attack.

Even were someone to throw a non-monk weapon like a two-handed sword at a monk, the monk would certainly catch it (with d10 + dex mod + monk level almost always > d4). Then for the price of one ki point they could throw it back and get not only the martial arts damage die but proficiency bonus as well.

Compare that to a monk that takes a monk weapon like a shortsword, something with which they already have proficiency, and chooses to throw it. At the cost of losing their proficiency bonus, rather than spending a ki point, does it make sense to give them the martial arts damage? True, it adds to their ranged damage options, but only to sixty feet and with disadvantage after twenty. It is still a DM's judgement call as to whether to allow this, but in my opinion it is not overpowered.