NumGrid vs Mastermind
Mastermind is the 1971 plastic-peg deduction game that taught a generation how to think like a code-breaker. NumGrid is a 2026 browser puzzle that reuses the deduction loop with digits. They share DNA, but the player experience is meaningfully different.
The mechanic
Classic Mastermind hides a sequence of four colored pegs drawn from six colors (1,296 possible codes, or 6^4). After each guess you receive two numbers: how many of your pegs are the right color in the right slot, and how many are the right color in the wrong slot. Crucially, you do not learn which of your pegs earned which feedback. The peg feedback is anonymous.
NumGrid hides a 5-digit number (100,000 possible codes, or 10^5). After each guess every digit lights green (right digit, right position), yellow (right digit, wrong position), or gray (not in the answer). Each piece of feedback is anchored to a specific position. On top of that, NumGrid gives two free hints every day: the digit sum of the hidden number and its parity.
Search space, narrowed
Mastermind’s 1,296 codes feel smaller than NumGrid’s 100,000 — but NumGrid’s free hints typically collapse the working set to between 800 and 3,500 candidates before you guess once. After the parity hint, halve it. A disciplined NumGrid opener can leave you with under 50 candidates by turn 2.
Feedback, compared
| Game | Feedback | Positional? | Free hints |
|---|---|---|---|
| Mastermind | Two counts (black/white pegs) | No — anonymous | None |
| NumGrid | Per-position green/yellow/gray | Yes | Digit sum + parity |
Optimal play, compared
Donald Knuth proved in 1977 that any Mastermind game is solvable in five guesses or fewer using a minimax algorithm. The expected solve count under perfect play is 4.476 guesses. Most human Mastermind players average 5-7 guesses; expert players average 4-5.
NumGrid with disciplined play averages 3-4 guesses. The combination of per-position feedback and free hints means an expert can usually win in 3, and a well-prepared opener can win in 2 on lucky boards.
Which is the better brain workout?
Mastermind is more demanding because the anonymous feedback forces you to hold more hypotheses in working memory. You cannot collapse to certainty as fast. NumGrid is more forgiving: the positional feedback and free hints turn it into a constraint-satisfaction puzzle rather than a memory + deduction puzzle.
If you find NumGrid easy, try playing it Mastermind-style: cover the digit sum, parity, and the position information of your guesses, and see whether you can still solve it. Removing the free hints makes it feel like a different game.
Why the daily format matters
Mastermind has never had a great daily-puzzle adaptation because peg setups feel repetitive day to day. NumGrid’s daily-puzzle structure — one shared puzzle per day, shared with friends, with an archive of past puzzles — gives it social and collection dynamics that the original board game cannot offer.
FAQ
Is NumGrid basically a daily version of Mastermind?
Mechanically related, but not the same. Classic Mastermind hides a 4-peg code of 6 colors and returns abstract feedback (count of correct color in correct position, count of correct color in wrong position) without telling you which peg got which feedback. NumGrid hides a 5-digit number and returns per-position Wordle-style feedback (green/yellow/gray, with the position attached). The per-position feedback in NumGrid is far more informative per guess.
Which game is harder?
Classic Mastermind is harder per guess because the feedback is positionally anonymous. NumGrid is easier per guess because feedback is anchored to the position, and the free digit-sum and parity hints collapse the search space before your first guess. Mastermind has a 1,296-code space, NumGrid has 100,000 — but the hints make NumGrid feel smaller.
What is Mastermind's mathematical solve count?
Donald Knuth proved in 1977 that classic Mastermind (4 pegs, 6 colors, no blanks) is solvable in 5 guesses or fewer from any opening. With perfect play the expected solve count is 4.476 guesses. NumGrid with hints used correctly averages 3-4 guesses, putting it in the same range as expert Mastermind play.
Does Mastermind strategy transfer to NumGrid?
Yes — the core skill of constraint narrowing transfers directly. The biggest carryover is the discipline of using a guess to maximize information gained rather than to try to win. In NumGrid, your second guess is often a "scouting" guess that splits the remaining candidate set rather than an attempt at the answer.
Try the deduction loop today — play today’s NumGrid puzzle →
New here? How to play NumGrid covers the rules in two minutes. For deeper play, read the strategy guide or compare with Bulls and Cows.