A word ladder gives you two words and asks you to climb from one to the other, changing a single letter at a time, where every step is itself a real word.
COLD → CORD → WORD → WARD → WARM
Lewis Carroll invented the format in 1877 and called it “doublets”. It is still one of the purest word puzzles there is: no trivia, no obscure vocabulary, just the structure of English.
Work from both ends
The single most useful habit is refusing to solve forwards.
Build two rungs down from the start word, then two rungs up from the target, then look for something that joins them. Four-step ladders almost always meet in the middle, and searching from both directions halves the depth you have to hold in your head.
Solving forwards only feels productive because every step is a valid word. But a valid step is not the same as a step toward anything, and a chain of four plausible-looking forward moves frequently arrives somewhere with no route to the target at all.
Move the vowel
In four-letter English, the vowel slot has far more neighbours than any consonant slot. BAT gives you BET, BIT, BOT, BUT; CAT gives you COT and CUT. Consonant positions are much thinner.
So the vowel is your flexibility. Locking it early — deciding on rung two that the vowel will be an A for the rest of the ladder — is the most common way people strand themselves.
The corresponding rule for targets: if the start and the target have different vowels, the vowel change is usually not the last move. Getting it out of the way early keeps your options open for the harder consonant transitions.
Fix one letter at a time
A rung that suddenly matches two letters of the target looks like progress and usually is not.
Optimal ladders tend to correct a single position per step, because each change has to leave a real word behind. A move that fixes two positions at once has to thread a much narrower needle, and the words that allow it are rare enough that they are usually detours rather than shortcuts.
If you find a move that fixes two letters, take it — but check first that the resulting word actually has neighbours.
Why some days are much harder
Word ladder difficulty has almost nothing to do with how hard the words are. It is about the shape of the graph.
Think of every four-letter word as a point, connected to every other word one letter away. Some words sit in dense neighbourhoods — BALL has more than a dozen neighbours — and ladders through them feel effortless because there is always another move.
Other words sit on bridges: thin connections between two regions of the graph where exactly one word links them. When a ladder has to cross a bridge, the entire puzzle collapses into finding that single word, and nothing else you try will work.
A hard day is usually a bridge day. Knowing that is oddly comforting — you are not missing five different options, you are missing one.
When you are stuck
Three things to try, in order:
- Change the vowel and see what appears. It is the cheapest move and it frequently opens a new region.
- Go back a rung. Ladders have dead ends and the fix is almost always one step back, not five steps forward.
- Work backwards from the target for two moves, listing every word that reaches it. That set is usually small, and it tells you exactly what you are aiming at.
About the daily puzzle
Ink Ladder generates a fresh pair each day from a curated list of common four-letter words — obscure and unpleasant words are excluded on purpose, because a ladder is only enjoyable when every rung is a word you recognise.
Par is computed by breadth-first search over the whole word graph, so it really is the shortest chain that exists rather than an estimate. Beating par is not possible; matching it means you found an optimal route.
Everyone in the world gets the same pair on the same day, and there is an answer and hints page that reveals as little or as much as you want.