Kata Shift
Find the rule. Then let it go.
How to play Kata Shift
Sort the top card onto the reference card it belongs with. The matching rule is hidden — correct-or-wrong feedback is your only clue.
After a set number of correct sorts the rule switches, and the new rule is never shown. Your first miss after a switch is free; keeping on sorting by the old rule costs a life. Tap a card or press 1–4.
What it trains: hidden-rule card sorting
Kata Shift is built on set-shifting, the skill probed by classic card-sorting tasks in cognitive research: infer a sorting rule purely from correct-or-wrong feedback, exploit it — and abandon it the moment it changes.
The hard part isn't finding the rule; it's letting go of one that just stopped working. Clinging to an outdated rule (perseverating) is exactly what the game punishes.
Does brain training work? →Based on the Wisconsin Card Sorting Test
In the Wisconsin Card Sorting Test you sort cards that vary in colour, shape and number onto four key cards. Nobody tells you the rule: you only hear whether each sort was right or wrong. After ten correct sorts in a row the rule changes without warning, and the key score is how often you keep sorting by the old rule (perseverative errors).
Kata Shift uses the same structure: four fixed reference cards, a hidden rule, and right-or-wrong feedback as your only clue. Its three dimensions are count, shape and fill instead of colour, shape and number. The rule changes after a set number of correct sorts (8 at the start, as few as 3 later). The new rule is never shown, but the level-up marks the moment of the switch. Your first miss after a switch is free, and sorting by the old rule after that costs a life, which is the game's version of a perseverative error.
Grant, D. A., & Berg, E. A. (1948). A behavioral analysis of degree of reinforcement and ease of shifting to new responses in a Weigl-type card-sorting problem. Journal of Experimental Psychology, 38(4), 404–411. doi.org/10.1037/h0059831
Berg, E. A. (1948). A simple objective technique for measuring flexibility in thinking. Journal of General Psychology, 39(1), 15–22. doi.org/10.1080/00221309.1948.9918159
Scoring & progression
Runs are endless: you climb levels until your lives run out, and scoreboards track the highest level you reach. Strong runs feed your belt progression in the logic discipline — from white belt toward black — and your place on the global leaderboard.
Kata Shift FAQ
Is Kata Shift free to play?
Yes. Kata Shift runs in your browser with nothing to download, and you can play it without an account. An account only saves your scores, stats and leaderboard place.
How long does a run of Kata Shift take?
There is no fixed length. Levels keep coming until your three lives are gone, and scoreboards record the highest level you reached.
What do I need to play Kata Shift?
A modern web browser. A desktop or laptop with keyboard and mouse works best; the game also runs on tablets and phones with touch controls.
Is Kata Shift the same as the Wisconsin Card Sorting Test?
Kata Shift is built on the Wisconsin Card Sorting Test, with some differences. Kata Shift uses the same structure: four fixed reference cards, a hidden rule, and right-or-wrong feedback as your only clue. Its three dimensions are count, shape and fill instead of colour, shape and number. The rule changes after a set number of correct sorts (8 at the start, as few as 3 later). The new rule is never shown, but the level-up marks the moment of the switch. Your first miss after a switch is free, and sorting by the old rule after that costs a life, which is the game's version of a perseverative error.