
Of all the permanent upgrades in Blue Prince, the Axe grants you some of the best boons you could ask for in your exploration of the Mt. Holly manor. Sold for 32 Gold in the Armory, the Axe lets you nullify the Gem cost of one room forever. Once the item is in your inventory, open up your Room Directory, select the room you no longer wish to pay for, and you’ll see a prompt to use the Axe.
Fortunately, this isn’t a one-and-done item; you’ll have a chance of seeing the Axe spawn again in the Armory on subsequent runs. However, it appears that the Axe will not spawn again after you’ve used it three times. You can’t infinitely grind for this item across hundreds of in-game days to ensure you never have to collect a Gem ever again.
Ultimately, the best rooms to use the Axe on in Blue Prince will depend on your playstyle. However, if you just want to get the most bang for your buck, consider slashing the Gem costs of any of these five rooms.
Below you’ll find some mild spoilers for Blue Prince. Having said that, few if any of the reveals below should be new to you by the time you actually get an Axe in your inventory. We’ll explain what’s in these rooms that’s worth a use of the axe, but if you just want the names, they are as follows:


Trophy Room

I know I just said that the best room choices would depend on your playstyle, but it’s really hard to argue that any room deserves the Axe more than the Trophy Room. It awards a luxurious eight Gems as a prize, but you have to consume five Gems just to draft it. Sure, a net gain of three Gems is nice, but the high cost of entry means you’d have a healthy reserve of Gems coming in here anyway. Even worse, you run a huge risk of drawing this room when you can’t afford to draft it, making the Trophy Room actively harmful to your room deck.
The Axe single-handedly transforms the Trophy Room from a liability to the best room in the game. Removing the Gem cost means you’ll grab all eight gems with no consequence, which is more than enough to draft any room you’d see afterwards. The Trophy Room isn’t a Dead End either, giving it a leg up over rooms like the Wine Cellar. This is a Rare room by default, so you won’t necessarily catch it every run. Regardless, you don’t want to pass up this huge upgrade.
Attic

Even though it’s a Dead End room, the Attic offers enormous value to any run of Blue Prince. It contains eight items, which can include Gems, Keys, Dice, or major finds like rare keys or tools like the Metal Detector. The Attic is so valuable that you’ll often earn back the three Gems you’d normally need to spend drafting it!
By removing the Gem cost from the Attic, you’ll ensure you can draft this room at any point during your run. After all, it’s when you don’t have a healthy stock of resources to spend that you’ll really want to find an Attic! And even if you’re on a great run, keeping three extra Gems in your pocket is always nice. This is a room you’ll be dying to use regardless of where you are in your overall progression of Blue Prince, making it a safe use of your Axe.
Cloister

The Cloister is a great compliment to the Attic since it serves the opposite purpose: adding a bunch of extra doorways to your house. You’ll likely find items in the Cloister too, since it’s a Green Room with spots you can dig up with a shovel. Additionally, this room can grant some useful buffs if it comes up when you use an Upgrade Disk (such as chances to get permanent upgrades whenever you draft it).
You’ll always feel happy to see this outdoor reprieve in your draft pool, as it virtually guarantees you’re not going to hit a dead end to your run just yet. By removing the three-Gem cost, the Cloister will never be out of reach when you need it most.
Rotunda

The Rotunda is here as an alternative to the Cloister. It technically offers the same amount of doorways the Cloister does, just with a slightly clunky gimmick of pressing a button in the center to switch which doors you can access. And when you’re drafting from the Rotunda, you’ll have the option to rotate any Rooms you draw. This isn’t always useful, but it can prevent certain rooms from leading you straight into a wall.
In the unlikely event that you’re purchasing multiple Axes in a Curse Mode playthrough, the Rotunda is better than the Cloister since it’s classified as a Blueprint. Otherwise, the Rotunda mainly beats out the Cloister in the event that you didn’t get one of the more helpful upgrades for it.
Vault

The value of the Vault depends on your overall progress in Blue Prince. In the early to mid-game, an infusion of 40 Gold is a really big deal, even at the cost of three Gems. That’s enough to potentially buy out an entire Commissary, and you’ll eventually need hundreds of Gold in a single run to purchase the game’s most expensive upgrades. That said, as your allowance grows, 40 Gold won’t look as impressive. And once you’ve bought the most expensive items in the game, Gold becomes a smaller priority to grind for.
However, the Vault is also home to critical clues you’ll need to solve several central mysteries in Blue Prince. To get these clues, you’ll need to find certain keys and bring them to the Vault during a single run. This is already an RNG-(Random-Number-Generated)-reliant task, so axing the Gem cost ensures you won’t get stuck when you really need to draft this room. Even with the diminishing returns as you play, that benefit alone can justify using one of your three Axes.
Use the Axe on these rooms to make specific challenges easier
These two rooms aren’t quite as useful during your average run of Blue Prince, but you might consider using the Axe on them if you’re solely focused on accomplishing certain objectives.
Classroom

The Classroom is mildly useful at best on its own, so cutting the single-Gem cost won’t add a lot of value most of the time. That said, if you’re gunning for a certain optional challenge, you’ll need to draft the Classroom nine times in a single run. You’ll already need a lot of luck to pull this off, and dedicating so much of your house to Classrooms doesn’t leave a lot of room for Gem grinding. By using the Axe on the Classroom, you’ll functionally save yourself nine Gems over the course of one attempt.
Throne Room

At a cost of five Gems, the Throne Room is tied with the Trophy Room as the most expensive room to draft in Blue Prince. As the ominous “Reclaim the crown” text implies, you’ll need this room for some significant story unlocks. The Throne Room also features three doorways and an elusive lever to Room 46, saving you from the long hike you’d normally need to do to open this room.
If you do use the Axe on the Throne Room, you’ll certainly make use of it whenever you happen to draft it. However, the Throne Room just doesn’t offer that much value compared to other rooms you could choose. You’ll get more doorways out of the Cloister or the Rotunda, and the Room 46 lever really isn’t that important by the time you’re likely to have this room in your deck. Still, for those key runs where you specifically need to get the Throne Room, the Gem cost reduction can come in clutch.
Blue Prince is available now on PS5, Xbox Series X/S, and Windows PCs.