Gridz

Gridz calls itself a crossword without the clues, and that is the entire design. You get a crossword grid with its black squares in place and nothing else: no numbers, no across list, no down list. Every white square has to be filled so the letters spell words in both directions, and the only constraint keeping you honest is the crossings. Three grids land each day, a 5x5 Mini, an 8x8 Main and a larger Mega, and the site says the week ramps from a Monday warm-up to a Sunday summit.

1. Pick Mini, Main or Mega at the top of the board, or step to another date with the arrows either side of Today.
2. Type or tap letters into the highlighted square. The Across toggle under the keyboard flips you between filling across and down.
3. Watch the keyboard while you fill: it highlights the letters in play for the word you are currently in.
4. When you are stuck, use check or reveal on a single letter, on the word, or on the whole grid.
5. Finish the grid against the running clock, which sits beside a counter of how many of the grid's words are done.

Take the clues out of a crossword and you find out how much of the solve was ever about them. What is left in Gridz is pure constraint satisfaction: you guess a plausible word, and the grid either accepts it in the perpendicular direction or quietly refuses. The three sizes matter more than they look, because the Mini is small enough that a single wrong crossing is obvious and the Mega is one where a bad guess propagates for ages, and the highlighting keyboard is the one concession that stops the whole thing collapsing into brute force.

The grid does not colour a letter as you type, but it does keep count: as words land, the word counter under the board advances and the progress bar fills with it. For a verdict on the letters themselves you have to ask, through check or reveal, and the site states the colour code plainly, correct letters turn green and wrong ones turn red. Two readouts run under the board the whole time, a word counter and a timer. The keyboard is the live signal instead: it lights the letters belonging to the word you are filling and greys the rest, so it narrows the alphabet for you square by square.

Mini

The 5x5 daily, the quick one.

Main

The 8x8 daily.

Mega

A bigger grid, the third of the day's three.

• Play the crossings, not the words. With no clues, a letter is only ever justified by the fact that it works in both directions at once, so the squares where two long entries meet are where the grid actually gets solved.
• Read the keyboard before you type. It narrows itself to the letters relevant to the word you are in, which is the closest thing to a clue this game offers.
• Check a single letter before you rip out a whole word. The check tool works at letter, word and puzzle level, and the cheapest of the three usually settles the argument.
• If the Sunday grid is beating you, come back on Monday. The site says puzzles ramp up across the week from a Monday warm-up.