Hidden Code

What is Hidden Code?

Hidden Code is the classic pencil-and-paper code game known as Bulls and Cows. A code of different digits is hidden, and you crack it by guessing. Every guess is answered with two numbers: how many of your digits are in the right place, and how many are in the code but in the wrong place. Nothing else is given away, so each answer is a small clue, and the clues add up.

There are three levels: a code of 3 digits in 10 guesses, 4 digits in 10 guesses, and 5 digits in 12 guesses. Every day brings a new 4-digit code, the same for everyone, so you can compare your result with your friends.

How to play

Type a guess on the digit pad and check it; the answer appears next to it in the list of guesses.

• Digits. The code uses different digits, and so does every guess. A 0 may come first.
• Answers. A solid dot counts the digits in the right place; a ring counts the digits that are in the code but in another place. An answer of 0 and 0 tells you that none of those digits is in the code.
• Notes. Tap a digit in the notes row once to rule it out and again to mark it sure. Your notes show on the pad and in the list too.
• Editing. Tap a place in your guess to change it. Typing a digit that is already in the guess moves it to the place you picked.
• Hints. A hint rules out a digit that is not in the code, one you could not yet be sure of, and adds 90 seconds to your time.
• Score. Crack the code to score 2000 points, plus 200 for every guess you had left, minus a point for every second. A code you do not crack scores nothing. Every level has its own leaderboard.

Strategy tips

1. Spend the first guesses on new digits. Two or three guesses with no digit in common show you, between them, roughly which digits the code uses.
2. Make every guess fit every answer. Before you check, test your guess against each earlier answer as if it were the code. A guess that fits them all can still be the answer.
3. Use digits you have ruled out as fillers. A guess made of one digit you are testing and digits you know are out tells you exactly about that one digit.
4. Move one thing at a time. Swap two digits, or change one digit, and compare the answer with the one before: the difference points straight at what you changed.
5. Keep your notes up to date. Marking a digit out the moment you are sure of it saves you from using it again by mistake.

FAQ

Is Hidden Code free to play?

Yes. Like every game on Play, it runs free in your browser, with no download and no account needed.

Is this the same game as Bulls and Cows?

Yes. It is the traditional digit game, with the two answers known as bulls (right place) and cows (wrong place). It is older than the well-known board game with coloured pegs, which plays the same idea with colours.

What does a hint do?

It rules out one digit that is not in the code. It never picks a digit your answers already prove is out, so it always tells you something new. Each hint adds 90 seconds to your time.

What is the daily code?

Every day everyone gets the same 4-digit code, so your guesses and your time compare directly on the leaderboard.

How is my score counted?

A cracked code scores 2000 points, plus 200 for every guess you had left, minus one point for every second from the first look to the last guess, with 90 seconds added for each hint. It never drops below 100, and a code you do not crack scores nothing.