One-change word ladder: rules and printable materials

Change one letter or character at a time while keeping every intermediate entry a valid word.

Players

1–6

Plan for

10–18 minutes

Bring

Two word-route cards, pencils and checked word lists

Choose a checked route

Use the supplied English cards COLD to WARM and CAT to DOG. Every entry must keep four letters on the first card or three on the second. Only ordinary English words are used in the provided key. The Chinese companion page uses separate two-character word examples; it is not a claim that translated English letters form Chinese words. One to six people can work cooperatively.

Change one written position

Replace exactly one letter per step, keeping all other positions unchanged. You may not reorder letters, add or delete a letter, or jump across a non-word. Agree an available dictionary or the host’s prechecked word list before starting; pause disputed additions instead of accepting a convenient spelling after seeing a solution. A word’s meaning may change completely.

Worked first route

COLD → CORD → CARD → WARD → WARM is valid. Each neighboring pair differs in exactly one position: third, second, first, then fourth. COLD → WARM is not one move because all four positions change. Count changes, not words: five words form four moves. The printed route has enough rows for a non-minimal solution.

Try the second card

CAT → COT → COG → DOG is a checked route of three changes. A team may find another route if every word is accepted and every adjacent pair passes the one-position check. Keep answer keys folded until the attempt ends. Teammates rotate the pencil after each proposal, and may cross out a rejected step without restarting the whole card.

Stop and review

Finish after both endpoints are reached or the agreed twelve minutes; then inspect every step together. There is no fastest-reader award or promised minimum move count. A helper may write dictated letters. For a new card, check a complete route in advance and label its language. Do not advertise an arbitrary pair of words as solvable without a verified route.

Printable materials

Preview at 100% scale, with browser headers and footers off. Cut with suitable help. Keep host keys separate. This is a manual tabletop kit, not an online opponent, automatic judge or solver.