TenSecondCheck

Reaction game

Green light — hit it. Red cross — leave it. Thirty seconds, three lives.

Runs in your browser only

Score 0
Streak 0
Lives

Hit the green, dodge the red

Lights appear in the grid. Hit the green ones as fast as you can and leave the red crosses alone. Thirty seconds, three lives.

  • Hit it — the faster, the more points
  • Leave it — hitting it costs a life

On a keyboard, use Q W E / A S D / Z X C or the number pad — the keys are laid out like the grid.

How to play

Press Play. After a three-second countdown, lights start to appear in the nine cells of the grid.

  • A green light with a target means hit it. Tap it, click it, or press its key. The faster you are, the more points you get.
  • A red light with a cross is a trap. Leave it alone and it disappears by itself.

Each light only stays on for a moment, and a thin bar along its bottom edge shows how long it has left. A round lasts 30 seconds. You have three lives: missing a green light or hitting a red cross costs one. When the time runs out or the lives are gone, the round ends and your results appear below the grid.

Colour is never the only clue. Green lights carry a target and red lights carry a cross, so the game can be played by people who do not tell red from green easily.

Playing with a keyboard

The grid maps onto keys that sit in the same pattern on almost every keyboard: Q W E for the top row, A S D for the middle and Z X C for the bottom. The number pad works too, with 7 8 9 at the top. The game reads the physical position of the key, not the letter printed on it, so a Russian, Ukrainian, French or German layout plays exactly the same.

Rest three fingers on the middle row before the countdown ends. Moving a whole hand across the keyboard costs far more time than any difference in reflexes.

How points are counted

  • A green light hit in 250 ms is worth 75 points; one hit in 600 ms is worth 40. The slowest hit still earns 10.
  • Streaks multiply your points: five green lights in a row without a mistake give ×1.5, ten in a row give ×2.
  • A red cross you hit takes away 50 points, breaks the streak and costs a life.
  • A missed green light earns nothing, breaks the streak and costs a life.
  • A tap on an empty cell breaks the streak but does not cost a life, so an unlucky finger on a phone is not punished too hard.

The lights come more often and stay on for less time as the round goes on, and the red crosses only start after the first few seconds. The first half rewards speed; the second half rewards staying calm.

Why the red crosses matter

Reacting quickly is only half of real-world reaction. The other half is not reacting when you should not: braking only for the car that is really stopping, or not firing at a teammate in a game. Psychologists study this with so-called go/no-go tasks, in which a person must respond to one kind of signal and hold back on another. The red crosses turn the game into a simple version of that idea.

That is also why guessing does not pay. If you press as soon as anything lights up, you will lose lives on the traps long before the time runs out.

Game or test: which one should you use?

The two tabs above the grid switch between them.

The reaction time test is the right choice when you want a clean number, to compare days or to see whether a mouse or screen adds delay. It measures your response to one expected signal, five times, and takes an average.

The game measures something closer to everyday situations: find the target, decide, and act, while ignoring distractions. Its reaction times are naturally slower. Choosing between several possible answers takes longer than responding to one you already expect, an effect known in psychology as Hick’s law. Do not compare game times with test times; compare each with itself.

Tips for a higher score

  • Look at the centre cell, not at the corners. From the middle, every cell is within easy reach of your side vision.
  • Do not chase a light that is about to go out. If its bar is almost empty, get ready for the next one instead.
  • On a phone, use both thumbs and hold the phone in landscape if the grid feels cramped.
  • Plug in a laptop and close heavy tabs. A busy computer can show lights a frame late.
  • Play a few rounds. Scores usually rise quickly over the first several games as you learn the rhythm, then level off.

Challenge a friend

After a round, type your name if you like and press Create the challenge link. Your friend gets exactly the same lights, in the same cells, at the same moments, so the only difference between your scores is how you played. When they finish, both scores appear side by side, and they can send a rematch back with both results inside.

The link carries only a short code for the light sequence, your name and your score. They sit in the part of the address after the # sign, which browsers do not send to any server.

Want a clean measurement instead of a game? Switch to the reaction time test. If your clicks feel late, check the buttons with the mouse test, and if you play on a controller, the gamepad test shows whether every button registers.

Questions and answers

Is this game the same as the reaction time test?
No. The reaction time test measures one thing cleanly: how fast you respond to a single signal you are already waiting for. The game adds a choice of nine cells and red crosses you must not press, so it also depends on where you look and how well you hold back. Use the test for a number and the game for practice and fun.
Why is my average reaction in the game slower than in the test?
Because you have more to do. You first have to find the light and decide whether it is green or red, and only then press. Decisions with several possible answers take longer than a response to one expected signal, so a gap of 100 milliseconds or more between the two is normal.
Does the game flash quickly?
No. A new light appears at most about twice a second, only one cell of the grid changes at a time, and the screen never flashes as a whole. If bright changing colours are uncomfortable for you anyway, stop playing — the reaction time test changes colour only once per try.
Where is my best score stored?
Only in this browser on this device, next to the language and theme you picked. It is never sent anywhere. Clearing the browser data, or playing in a private window, resets it.