How to Play Nexus

1. Objective

A word ladder gives you two words of the same length: a start and a target. Your job is to turn one into the other by changing a single letter at a time, and every word you make along the way has to be a real word.

Here is the ladder Lewis Carroll used when he published the puzzle, turning HEAD into TAIL in five moves:

That is the whole rule. Nothing is anagrammed, nothing is added or removed, and the words never change length.

2. The Daily Ladders

Three ladders publish every day, one per length:

• Easy: four-letter words. Free, and no account needed.
• Medium: five-letter words.
• Difficult: six-letter words.

Medium and Difficult need an account, and they unlock by climbing: solving a ladder opens the next one, that same day. Yesterday's solve does not open today's Medium, and an attempt that does not solve opens nothing.

You get one attempt at each puzzle, so a ladder you submit is the ladder that counts. Everyone gets the same three ladders on the same day, and the board carries a countdown to the next set.

3. Building It

The start word sits at the top of the board and the target at the foot, both fixed. Between them the board opens exactly as many blank rows as the par route needs. Type a word into each row, and the tile that changed lights up so you can see your move land.

Three controls:

• Add step: adds a row. Take it when your route needs more moves than par. There is no penalty for the row itself, only for the longer ladder it makes.
• Check ladder: submits what you have built. The server revalidates every rung, so a typo or a word that is not in the list comes back marked rather than silently accepted.
• Give up: ends the attempt and reveals the par ladder. It counts as your one attempt.

4. Par and Rating

Par

Par is the shortest route that exists between the two words. It is not an estimate: every puzzle is checked against the full word list before it publishes, so no shorter ladder is hiding. Matching par is the best possible result, and par cannot be beaten.

A longer ladder still solves the puzzle and still scores, just for a little less per extra step. A board you do not solve is not a zero either: the sound rungs you built before stopping still count for something, so a ladder that got most of the way is worth more than one that never started.

Rating and Streaks

Signed-in players are rated. Every player starts at 1500, and each rung is itself rated, so the three ladders are not worth the same: Difficult is a stronger opponent than Easy, and beating it moves you further.

A day counts towards your streak as soon as you solve any one of its ladders; you do not have to clear all three. A day you have not played yet does not break it, because that puzzle is still open.

Your rating ranks you on the Nexus leaderboard, and feeds the one Overall rating BattleGuess keeps for you across every game you play. Guests can play Easy every day, but only signed-in players are rated. For questions, contact .

5. Where the Word Ladder Comes From

The puzzle is older than almost anything else you can play online. Lewis Carroll invented it in 1877, and published it as Doublets in the magazine Vanity Fair from 1879. He called the two given words a doublet and the words between them links, and HEAD to TAIL above is his own example.

The rules have not needed changing since. What a daily version adds is a par, so there is a target beyond simply arriving, and a rung to climb once you do.

6. Tips

• Work from both ends. Ladders are far easier to find backwards from the target than forwards from the start, and a route that meets in the middle is still a route.
• Change vowels first. Swapping the vowel usually leaves a real word, so it moves you without stranding you.
• Count the letters that differ. That number is the fewest moves possible, and par is often exactly it, or one or two more.
• Do not fear a long route. Solving over par beats not solving, by a lot.
• Play Easy first. It is free, it unlocks Medium for the day, and it starts the streak.