Word Ladder

You start on one four letter word and have to reach another. Each step changes exactly one letter, and every word you pass through has to be a real word in the dictionary. COLD to CORD to CARD to WARD to WARM is a ladder. COLD straight to WARM is not.

Tap the letter you want to change on the bottom rung, then press a letter on the keyboard. If it makes a real word, it becomes your next rung. If it does not, nothing is lost and you can try another letter. The target sits underneath your ladder in faded tiles so you can see at a glance which positions still have to change.

If you get stuck, the Hint key lists every real word you could move to from where you are, with the ones that put a letter in its final place shown first. Tap one to take it.

The letter that changed is highlighted on each rung so you can see the route you took. There is no limit on how many steps you use, but the shortest possible route is shown before you start and revealed properly when you finish.

The puzzle is the same for everybody on a given day and a new one arrives at midnight.

Work from both ends. Write the target underneath the start and look at which letters already match. The positions that differ are the ones you have to change, and the order you change them in is the whole puzzle.

Vowels are the hinges. Most four letter ladders turn on swapping the vowel. CAT to COT to COG moves further than trying to change two consonants in a row, because changing a vowel almost always leaves a real word behind.

Beware of dead ends with rare letters. Words containing J, Q, V, X or Z have very few neighbours. If your route passes through one, it is usually the wrong route.

Common endings give you room. Words ending in -ALL, -AND, -ARE and -INE have dozens of neighbours each, so routing through one of those families gives you many more onward moves than routing through something unusual.

If you get properly stuck, the word finder will list every word matching a pattern, which is a fast way to see what a given rung can become.

A word ladder needs the entire dictionary arranged as a graph: every four letter word connected to every other four letter word that differs from it by exactly one letter. Most puzzle sites do not have that, because most puzzle sites are not built on a word database.

This one is. The same 5,469 four letter words behind the unscrambler are what make the ladder possible, and every daily puzzle here has been solved in advance so the shortest route is known rather than guessed at.