Warning: spoilers ahead for season 2 of His Dark Materials.
In season 2 of His Dark Materials, the TV adaptation of Philip Pullman’s book trilogy of the same name, viewers are introduced to a curious object, named the Subtle Knife.
As fans of the book series will be aware, The Subtle Knife is the title of the second novel, following on from Northern Lights and preceding The Amber Spyglass.
As the second season of the show is based on The Subtle Knife, the weapon – which Lyra Silvertongue (Dafne Keen) and Will Parry (Amir Wilson) are on a mission to retrieve in the fourth episode – carries huge significance, which the young protagonists are yet to discover.
So what exactly is the Subtle Knife and why is it so important?
What is the Subtle Knife in His Dark Materials?
The Subtle Knife is a knife which can be used by its wielder to cut windows into different worlds.
Also known by the name ‘Æsahættr’, the knife’s blade is double-edged and made from two different materials.
While one side of the blade allows its bearer to cut finely through any object, the other is able to find gaps in thin air, which can be cut through in order to travel between universes.
The knife was made by members of the Guild, philosophers who operated from the Torre degli Angeli in Cittàgazze, the city where Lyra and Will travelled to from their respective worlds.
What are the rules of the Subtle Knife?
If an individual in the His Dark Materials universe becomes a bearer of the Subtle Knife, they are supposed to follow a certain set of rules.
The first rule is to never open a window without closing it, as otherwise this would leave a portal into another world open for anyone to walk through.
The second rule is to never let anyone else use the knife, while the third rule is to never use the weapon for a ‘base purpose’.
We’ll just have to see how the Subtle Knife impacts Lyra and Will’s destinies in the upcoming episodes of His Dark Materials!
His Dark Materials airs on Sunday evenings at 8.10pm on BBC One.