I still remember the first time I saw the Simple Key in Bone Bottom. Five hundred rosaries for a key felt like a scam. After dozens of hours in Hollow Knight: Silksong, I can tell you it is not. These keys unlock some of the most valuable rooms in Pharloom, from powerful tools to story moments you do not want to miss. There are four Simple Keys in the game. Each one is tied to a specific area, and each one opens a specific door. I will walk you through every location and every lock.

Quick Reference

Simple Key #1: Bone Bottom

The first Simple Key is sold by the merchant in Bone Bottom. It costs 500 rosaries. That price is brutal when you first arrive. I tried to grind early and quickly realized it was not worth it. My advice is to continue the adventure and return later. By the time you clear a few areas, 500 rosaries feels much more manageable. The key is always there waiting.

This key pairs perfectly with the Wormways door above Bone Bottom. I used my first key there and immediately got a good return.

Simple Key #2: Songclave

The second key is also sold by a merchant, but she is not available immediately. You need to complete the Wandering Merchant quest. Grab the quest from the Wishboard. Once Jubilana returns to Songclave, she will sell you the key for 650 rosaries.

This price is higher than the first key. Luckily, Songclave is next to the long Citadel corridor. I used that spot to farm rosaries quickly. After a short loop, I had enough cash without too much pain.

Simple Key #3: Sinner's Road

The third key is different. It is not bought. It is dropped by a large chain-wielding enemy in Sinner's Road. Before you try this, make sure you have the Cling Grip from Shellwood. Without it, you cannot reach the arena.

I climbed a massive shaft full of spikes. At the top, the enemy dropped from above. The fight was tough but fair. Take him out and he drops the key. This one felt earned.

Simple Key #4: Sands of Karak

The fourth and final Simple Key is in the Sands of Karak. You can only reach this area once you have the Clawline ability from the Underworks in Act 2. The area is harsh. I died several times to environmental hazards.

You need to platform across vine puzzles from the left side all the way to the right. It does not take too long to find the key. At the far east, there is a bench. Rest there and grab the key. It is a quiet reward after a stressful trip.

Door Location #1: Wormways

This is probably the first locked door you will find. It sits just below the Wormways entrance, above Bone Bottom. I headed west from Mosshome, crossed the gap, and went through the cave with the acid spitter. The door is right there.

Opening it reveals more of the Wormways area. You can find the Sharpdart and the Plasmium Phials inside. For me, this was the best early use of a Simple Key.

Door Location #2: Sinner's Road

While exploring Sinner's Road, I noticed the Green Prince sitting in a cell. He does not beg you to open the door. I opened it anyway. It is absolutely worth it.

Later, the Green Prince appears in the Citadel. You learn much more about his story there. This door is not about loot. It is about lore. I still think it is one of the most memorable unlocks in the game.

Door Location #3: Deep Docks

This door is familiar from the Deep Docks. But do not be fooled. This is not an early game area. The enemies will shred you without proper tools and preparation.

If you are prepared, the area offers great tools like the Flintslate. The area is necessary for Act 3 progression. However, you can also reach it through the Far Fields once you have the Clawline. So this Simple Key door ends up being a little redundant. I would not prioritize this key unless you want a shortcut or extra challenge.

Door Location #4: High Halls

The final locked door is easy to find in the High Halls area. It is just left of the bench and before the dreaded Forum fight. I remember the panic of that fight.

Inside the room, you can find a huge number of rosaries and the Rosary Cannon tool. This tool is fantastic. If you can grab it before the Forum fight, it can make a noticeable difference.

My Recommended Order

Not every Simple Key has the same value at every stage of the game. This is the order I would follow in 2026:

1. 🥇 Simple Key #1 from Bone Bottom — buy it after you have a comfortable rosary supply.

2. 🥈 Open the Wormways door for Sharpdart and Plasmium Phials.

3. 🥉 Complete the Wandering Merchant quest and buy Simple Key #2.

4. 🏆 Grab Simple Key #3 from Sinner's Road and free the Green Prince.

5. 🎯 Save Simple Key #4 for later, then decide between Deep Docks and High Halls.

Simple Keys may look like a money sink at first. But every single one opens something worthwhile. I learned the hard way that ignoring them only made backtracking more painful. If you are still exploring Pharloom, keep an eye out for these keys. They are small. They are expensive. They are worth it.

Finding the right path in Pharloom often comes down to knowing where to spend your limited resources. The same logic applies outside the game. Whether you are hunting for a new metroidvania to scratch that same itch or simply want to stock up on titles without breaking your budget, a little research goes a long way. After all, a well-spent rosary is no different from a well-spent dollar.

If you are anything like me, finishing a run through Pharloom usually means immediately looking for the next great adventure. That is why I like to check the best game deals before committing to a full-price purchase. You never know when a hidden gem is sitting at a fraction of its usual cost, just waiting for someone savvy enough to grab it.