Why does the Keystone Tablet have only 4 slots for a word?
The Keystone Tablet comes with a set of 252 letters. The recovery seed is assembled manually and it is extremely easy to do so. You can use both sides of the Keystone Tablet, and store 12, 18, or 24 words.
That is up to 96 letters of sensitive information in a couple of minutes, ensuring the privacy and security of your data.
Why does it have only 4 slots for a word?
The Keystone Tablet is based on the BIP39 that is used to generate the mnemonic keys. It is a specific list of 2048 English words that has been carefully curated so that the entire word can be identified with just the first four letters. That is, four letters can be used to represent a unique mnemonic. That’s why the Keystone Tablet has only four-letter slots.
If you encounter a 3-letter mnemonic, you can fill the empty space with the blank side (reverse) of the letter tile.
The following picture is an example for your reference: