An old puzzle with simple rules
Word ladders go back to Lewis Carroll, who published them as a puzzle he called Doublets. The idea has hardly changed. You start with one word and must reach another by changing a single letter at a time, and every step along the way must be a real word.
On this site every ladder uses four-letter words. Each rung must change exactly one letter of the word above it, keep the other three in place, and use a word from the game's list of common English words. You cannot rearrange letters, and you cannot use a word twice in the same ladder.
Count the gap first
Before you type anything, compare the start and the target slot by slot. Count the letters that differ. That number is the fewest steps you could possibly need, because each step can fix only one letter.
Then compare it with par, which is the length of the shortest real route. If par equals the number of differing letters, a direct route exists, and you only need to find the right order. If par is larger, the ladder needs a detour. At least one letter will have to change to something temporary and then change again.
Here is a worked example. COLD to WARM has four differing letters, and it can be done in four steps: COLD, CORD, WORD, WARD, WARM. The trick is the order. Change L to R first, because CORD is a word and CARD or WORD follow easily. Changing D to M first would give COLM, which is not a word.
Now take LEAD to GOLD. Three letters differ, since both end in D. A short route is LEAD, HEAD, HELD, HOLD, GOLD. That is four steps, one more than the gap. The H is a stepping stone. It does not belong to either word, but it opens a path that the direct letters cannot.
Techniques that open routes
- Vowels are the hinges. Changing a vowel often moves you into a whole new family of words. If you are stuck on consonants, try swapping the vowel.
- Work from both ends. List the words that are one step away from the target. Then aim for one of those instead of the target itself. A ladder that looks long often shrinks once you know the last rung.
- Fix the hard letter last, or first. Some letters only fit a few words. If the target has an awkward letter, think about which words can hold it and route toward them.
- Keep common letters in place. A rung like HOLD can become BOLD, COLD, FOLD, GOLD, MOLD, SOLD or TOLD. Words with many neighbours are good places to pass through.
Common mistakes
- Changing two letters at once. COLD to CORK changes two letters. The board will reject it, but it is easier to check before you type.
- Walking into a dead end. Some words have very few neighbours. If you land on one and cannot move toward the target, press Undo to remove the last rung and try another branch.
- Ignoring used words. Each word can appear only once, and the start word counts as used. A route that loops back through an earlier rung will not work.
- Leaning on hints too soon. The Hint button fills the entry row with the next word on a shortest route from your latest rung. It is helpful, but each hint is counted in the summary, so try one more idea first.
Climbing the difficulty levels
There are three levels. Easy ladders have a par of 3. Medium ladders have a par of 4 or 5. Hard ladders have a par of 6 or 7. Your solved count is tracked separately for each.
Easy ladders are usually direct routes, so they are good for learning to order your changes. Medium ladders often need one detour letter, as in the LEAD to GOLD example. Hard ladders can need several. HAND to FOOT, for instance, has four differing letters but needs six steps: HAND, BAND, BOND, BOLD, FOLD, FOOD, FOOT. Two letters, B and L, appear only to bridge the gap.
A good goal on each level is to match par with no hints. Once you can do that often on Easy, move up. When a Hard ladder beats you, use one hint, then study where the route went. The detours you learn tend to come up again.
