A Comprehensive Guide to Warded Locks

Key Takeaway

  • Warded locks are old-fashioned mechanical locks that use obstacles called “wards” as their main defense mechanism. A key with only that specific pattern can unlock these locks.
  • Since they are susceptible to skeleton keys and impressioning, their practical use has been limited over a period of time. 

In a world where technology has permeated the locks industry (smart locks), there is an old world charm about warded locks. Today, you won’t find them often except for probably some cabinets that require minimal security. 

However, for a lock whose roots can be traced back to thousands of years in ancient China and Rome, understanding how they work can lead us to learn why they are near to extinction. Besides, the study presents as a good opportunity to know more about a different kind of lock. 

So in this guide, we’re going to dive into the world of warded locks, exploring how they work and what are some of its vulnerabilities. So join me on a journey to uncover the secrets of warded locks.

What is a Warded Lock?

What is a Warded Lock?

A warded lock is a locking mechanism that works by creating obstructions in the keyway that only a specific key with the same pattern can navigate and hence open the lock. The obstructions are known as the wards.

You could recognize warded locks from their weird looking keys with very creative cut patterns. Below is one example of the same –

Another way to understand how a warded lock works is by thinking of a manhole. Only the correct cover with the right diameter can cover the manhole. No other patterned cover will fit in.

History of Warded Lock

The history of warded locks goes back a long time, about 2,000 years. The idea of using wards to block access is believed to have started with the Romans. They used special keyway patterns to stop unauthorized entry. Over time, these locks became popular in medieval Europe. 

However in recent years, warded locks are not used for all practical purposes for their vulnerabilities – Skeleton Keys and Impressioning.

We will cover these vulnerabilities in detail in just a while but first let’s see the components and how they all come together to work.

How Does a Warded Lock Work?

To understand the operation of warded locks fully, we must explore their internal components and how they function together. 

Warded Lock Components

Warded locks consist of several essential components, each playing a distinct role.

1. Keyway: 

The keyway serves as the entry point for the key. It’s like the front door of the lock, allowing the key to interact with the lock’s inner mechanisms. You will find different cut patterns on the keyway (wards) that restrict any key to go through.

2. Wards: 

The most crucial element in a warded lock is the set of obstructions known as “wards.” These wards can be concentric plates or intricate protrusions within the lock. Their primary purpose is to block the rotation of a key that does not have corresponding notches or slots designed to fit through them.

3. Bolt: 

Needless to say, the bolt’s role is to lock the door. When the correct key is inserted into the keyway and turned, it lifts the bolt, effectively releasing it from its locked position. Generally the tip (end part) of the key interacts with the bolt directly. To know more about different parts of a key, refer to one of my earlier articles. 

4. Key Bits: 

Key bits are the bumpy parts on the key that go into the wards. These bumpy bits need to fit perfectly with the wards inside the lock. If they don’t match, the key can’t turn, and the lock won’t open. The pattern of these bumpy bits on the key must match the wards inside that lock.

Key Bits

Warded Lock Mechanism

The warded lock mechanism’s simplicity is one of its defining features. It relies on the key’s ability to align with and navigate the wards within the lock, ultimately lifting the bolt and unlocking the device. 

Warded Lock Mechanism

Let’s take a closer look at its operation:

  • Key Insertion: When a properly designed key is inserted into the keyway and turned, the key aligns with the wards inside the lock.
  • Ward Interaction: The key acts as a guide, allowing it to pass through the wards without obstruction. The specific shape and size of the wards match the key’s unique pattern, facilitating the key’s ability to navigate and bypass these barriers.
  • Bolt Elevation: As the key navigates the wards successfully, it engages with the bolt. When the key is turned correctly, it lifts the bolt, disengaging it from its locked position.
  • Unlocking: With the bolt elevated, the lock is effectively unlocked, permitting the opening of the door or access to the secured object.

Warded Lock Vulnerabilities

Warded locks aren’t as secure as modern locks. They have vulnerabilities that make them easy to open, especially with two techniques called skeleton keys and impressioning. Let’s look at these issues and see why warded locks aren’t very good for keeping things safe.

Skeleton Keys

Contrary to the popular misconception that “skeleton key” refers to all warded lock keys or antique keys, it is a specific type of key designed to bypass locks. It is a sort of master key with the serrated edge removed so that it may open a variety of locks, most frequently the warded lock.

Skeleton Keys

The brilliance of skeleton keys lies in their simplicity. By removing the unnecessary notches and grooves found in regular keys, there is nothing left to obstruct within the lock. This enables a skeleton key to glide effortlessly through the wards, effectively bypassing the lock’s internal barriers.

However, there is a limitation to this technique. Since warded locks come in various shapes and sizes, a single skeleton key cannot open all warded locks. So lock pickers would carry collections of skeleton keys, often referred to as “tryout keys,” enabling them to experiment with different shapes. For modern warded locks, it’s possible to purchase sets of lockpicks working on the same principle designed to work with most locks.

And since warded locks come in different patterns, if you happen to lose your key, it can become quite challenging to replace the old key.


Apart from skeleton keys, warded locks are also at risk from a method known as “impressioning.” This technique is used to make a new key for a lock when you don’t have an existing key or don’t want to take the lock apart to see how it works. 

Here’s how impressioning works:

  • Start by covering a key blank or any suitable item with a material that’s easy to scratch off, like wax, paint, or a marker.
  • Put the coated item into the lock’s keyhole and try to turn it like you would with a real key.
  • As the coated item moves past the fixed wards inside the lock, it leaves scratches on the coating. These scratches create an “impression” that shows where the wards are and what they look like.

The impression gives you a good understanding of where the internal obstructions (wards) are and their sizes and shapes. With this information, you can make a working key without needing the original key.

Frequently Asked Questions

Q1. Are warded locks still used?

Answer. Warded locks are still used in some low-security applications, but their use has significantly decreased due to inherent security vulnerabilities to skeleton keys and impressioning.

Q2. What is the difference between a pin tumbler and warded lock?

Answer – The main difference between pin tumblers and warded locks lies in their locking mechanisms. In a pin tumbler lock, a set of pins needs to sit flush with the sheer line by the key to unlock the lock, while warded locks rely on internal obstructions (wards) that the key must bypass. Pin tumbler locks are more complex and offer higher security compared to warded locks, which are relatively simpler but less secure.


In conclusion, warded locks have a rich history that dates back centuries and continue to be a fascinating aspect of lock technology. While they may not offer the same level of security as modern pin tumbler locks, warded locks still hold a unique place in the world of lock mechanisms. Their simple yet effective design and historical significance make them a subject of interest for locksmiths, historians, and lock enthusiasts alike.

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Hey! I am Mark. Though I am not a locksmith by profession, but locks have always fascinated me since my teens. And it all started when I got locked out of my house and I had to pick the lock. Since then it has become my hobby to learn more about different kinds of locks, understand their working and methods to pick them up. In due course of time, I have also become better aware of how installing the right lock goes a long way in ensuring iron clad security. I aim to share my passion (about locks) through this blog. If you are also passionate about picking locks or are just looking to beef up the security, hop on the ride.