If you thought this was neat, check out my perfect whetstone run of the entire fight here:

Whetstone sort of acts like a double jump on fights where the bosses either have really small or non existent hit boxes. I always use it for Devil as it can help dodging the goat attack in first phase and makes the final phases much easier by parrying the eyes. Rumor Honeybottoms and almost every other plane fight is great with whetstone.

Whetstone isn't great, but the ability to parry nearly anything is very powerful. The attack itself is pretty shit, and there are far better options - so yeah, Whetstone is a bad choice, but not a bad charm.

Whetstone honestly is probably one of, if not, my favorite charm. It's so fun basically being able to parry anything in the game with a hitbox. It opens up so many new ways to fight bosses, such as parrying Beppi's car when he dashes to you, the Snow Man when he rolls into you. Even racking up a little extra damage and using it alongside the spread with bosses without hitboxes that hurt (Howling aces 3rd phase dog, Carrot, Devil, Beppi 2nd and 4th). It's so fun, but there's so many other charms people can use, it only really shines with its inclusion with the Divine Amulet

Whetstone is extremely useful on plane fights, I find spamming bombs and the axe on things like dr kahls robot’s antenna, you can also get 5 hits + bombs with the super bomb immunity frames

Whetstone is actually nice for plane levels particularly Dr.Kahl and Cala Maria.

It’s especially useful in the robot fight when dealing with the things that come out of is belly in the first phase

It's good for dealing with bosses' summons/minions, they usually go down in a single whetstone hit (except for the radish and the umbrella)

Personally, I still prefer using Astral Cookie with Super Art II for this fight. Sticking to the top with Crackshot helps a lot, even on Expert.

Whetstone was my way to easily trigger sally's secret phase before Chalice was a thing.

Whetstone is very situational. Planes? Yes. A boss like goopy? No.

omfg I did not realize Whetstone let you parry the enemies directly that makes so much more sense

The only problem with most perks in cuphead is that they have to go against smoke bomb and the astral cookie so they aren’t bad they just don’t stack up to the other two

I never even knew you could parry a boss until now, even more the boss’s eyes

Stat wise, Whetstone deals the more damage than most other weapons. This is per hit, and I think only a fully charged charge shot deals more damage, as well as Special Moves.

There’s an achievement that in the game for beating an airplane boss with only the mini-plane bullets, there should be an achievement for killing a boss with only the whetstone

Whetstone is extremely useful for speedrunners

I got an idea for a fan made cuphead thing. Instead of being able to parry enemies, parrying deals damage to nearby enemies.

If you use the spread and the whetstone together then that’s a perfect match