How to Make a Crossword Puzzle

Every crossword starts the same way, with a blank grid and the uncomfortable feeling that there is nothing in it. What follows is the process that gets you from that blank grid to a finished puzzle: the rules that are genuinely rules, the conventions that are really preferences, and the judgement calls that only get easier with repetition.

There is a good reason to learn this properly rather than by trial and error. A crossword is not a list of words that happen to intersect. It is a designed object with a difficulty curve, a voice and a contract with the solver, and almost every decision that determines whether the finished puzzle is enjoyable gets made in the first hour.

Start with the theme, not the grid

A themed crossword is built around a set of long entries that share a hidden logic: they all contain a hidden animal, they all pun on the same phrase, they are all the same idiom with one letter changed. Everything else in the puzzle exists to hold those entries in place.

So the theme comes first. Brainstorm far more candidates than you need, then throw most of them away. A workable theme set usually needs three to five entries that satisfy four conditions at once:

• They share one clean logic. If you have to explain the connection in two sentences, the solver will never find it in one.
• They are symmetrical in length. In a standard grid the longest entries must mirror each other, so a 13 and a 9 need a 13 and a 9 to pair with.
• They are all equally good. One weak theme entry drags down the set, and solvers always notice the weakest one.
• They are findable. Real phrases people say, not constructions you assembled to fit.

Only when the theme set is locked do you touch the grid, because the theme dictates where the black squares can go.

The rules of the grid

These are the constraints that every mainstream outlet expects. Break them and your puzzle will be rejected before anyone reads a clue.

1. Rotational symmetry

The black square pattern must look identical when the grid is rotated 180 degrees. If the sixth square from the left in row four is black, the sixth square from the right in row twelve must be black too. This is a design convention rather than a solving aid, but it has held since the format was standardised, and a grid without it reads as broken even to solvers who could not name the rule.

2. Every white square is connected

The white area of the grid must be one continuous region. No island of squares cut off from the rest. This is what makes a crossword solvable by inference: a wrong guess in one corner is correctable from a crossing somewhere else.

3. Every letter is checked

Each white square must belong to both an Across and a Down answer. A square that only appears in one direction is an unchecked letter, and an unchecked letter is an unverifiable guess. British-style grids allow unchecked squares by convention; American-style grids do not.

4. Minimum entry length is three

No two-letter answers. There is no maximum, though anything above fifteen will not fit in a standard grid.

5. Keep the black square count low

Roughly one sixth of a 15x15 grid, or about 38 squares, is the working ceiling. The more black squares you spend, the more three-letter entries you create, and three-letter entries are where the ugly fill lives. A themeless with 30 blocks is elegant. One with 50 looks like a fence.

6. No repeated words

An answer cannot appear twice in the same puzzle, and a word in the grid should not appear in a clue for a different entry. Substrings are fine; whole words are not.

The rules exist to keep the puzzle fair. Everything past the rules is taste, and taste is the part that takes years.

Filling the grid

With the theme placed and the blocks set, you fill the remaining space. This is the longest part of the job and the part software helps with most, though it will not save a bad grid.

The working principle is that every entry in the puzzle should be a word or phrase a solver would recognise outside the puzzle. That standard rules out most of what is called crosswordese: ERNE, OLEO, ETUI, ANOA and the rest of the short vowel-heavy filler that exists only because it is easy to cross. Some of it is defensible in small doses, and we have argued the other side of that case, but the default is to avoid it.

Two practical habits make filling easier. First, fill the hardest corner first, usually the one with the longest stacks, because if it will not close you want to know before you have committed to everything else. Second, keep a scoring word list and be honest about the scores. If you keep waving through entries you rated 30 out of 100, your puzzle is a 30.

Writing the clues

Clues come last, and they are where you decide how hard the puzzle is. The grid is fixed by then; the difficulty is not. The same entry can be a Monday or a Saturday depending entirely on how you clue it.

A few conventions carry real information, and solvers rely on them:

• Tense and number agree. A plural answer takes a plural clue; a past-tense answer takes a past-tense clue.
• Abbreviations are signalled. If the answer is shortened, the clue signals it, with an abbreviation of its own, a word like briefly, or a source like the AP stylebook.
• A question mark means wordplay. It warns the solver that the definition is not literal.
• Foreign-language answers name the language. Either in the clue or through an obviously foreign context.

Beyond the conventions, write clues you would enjoy solving. Reference books help: a good dictionary such as Merriam-Webster settles spelling and sense disputes, and Wikipedia is useful for checking that a fact is actually a fact. Verify anything you are not certain of. A wrong clue is worse than a boring one.

Test-solve before you submit

Give the finished puzzle to someone who has never seen it and watch where they stall. You cannot test-solve your own grid; you already know every answer. What you are looking for is the corner that takes four minutes when the rest took twenty seconds, because that corner is unfair, not hard.

Then submit. Most outlets publish their requirements openly, including the New York Times crossword submission guidelines, and the constructor community at Cruciverb keeps a working list of markets and pay rates. If you want to know what an editor actually accepts, XWord Info lets you read the published record grid by grid. Our own guide to getting a first crossword published covers response times and the rejections you should expect.

Where to solve while you learn

The fastest way to develop taste is to solve constantly and pay attention to what annoys you. Daily grids from the major papers are the obvious training ground, and the puzzle-game side of the hobby is worth a look too: there are worked solutions for the CodyCross word game and for the Daily Themed Crossword if you want to see how commercial themed puzzles handle a constrained vocabulary. When you are hunting for fill ideas, a scrambled-word game like the daily Jumble is a surprisingly good warm-up, and a length-and-syllable reference such as this list of five-syllable words is handy when you need something long and clean to anchor a stack.

None of this guarantees a good puzzle. But the process is learnable, the rules are finite, and the only real requirement is that you finish things. A bad crossword you took all the way to a clue list will teach you more than three good ideas you abandoned at the grid stage.