The game of my childhood: Bulls and Cows or Mastermind.

Post-Cold War Russia of 1980th. We still believed that US is a threat and a serious competitor in the life style, science, sports and space. In school we trained to assemble and shoot from Kalashnikov and run to the bomb shelter (each school was equipped with one since World War II). I recollect perceiving US as a country of chewing gum, handsom guys like Tom Cruise, brown paper supermarket bags and homeless people sleeping under the bridge. The rest of my childhood was pretty much like yours - cartoons; after school sports, music, ballet; weekend ski, hikes, or friends and family gatherings.

One of the games I remember enjoying playing was a code breaking game named Bulls and Cows. All you need is a pencil and paper. Pick a 4 digit number with all the digits being different. This is your code. Ask your friend to break your code - guess this number.
Let's try it!
You pick 5817
My first guess is: 0123

You write my number under your number and see how many digits match. If I guess a digit correctly and it is in the same position as in your number, it is a "bull." Same digit but in a different position is called a "cow."
5817
0123 (0 bulls, 1 cow)

You tell me 0 bulls and 1 cow.

I give my second guess: 3456

You write again this number under your secret number in a column and reply how many bulls and cows are there in my guess:

5817
-----
0123 (0 bulls, 1 cow)
3456 (0 bulls, 1 cow)
6789 (0 bulls, 2 cow)

Now, I am using some logic to figure out that digits 3 and 6 are not in your number. Note that these digits present in two of my guesses and if either of them would be in your secret number the total number of bulls + cows would be higher than 4. I use these digits to guess the rest:

3698 (0 bulls, 1 cow) => only one of 9,8 is in your number
7836 (1 bull, 1 cow) => 7 and 8 are in your number
7048 (0 bulls, 2 cows) => 0, 4 are not in it, we know the place for 8 now
5872 (2 bulls, 1 cow) => 2 is not in it
1857 (2 bulls, 2 cows)
5817 Yes!

Perhaps you played this game as well - in US, Brazil, Egypt or Israel. Math is not only a universal language but also a toy shared across continents, cultures and regimes. According to Wikipedia, Bulls and Cows was known around the globe for hundred of years.

Nowadays, most of us here in US know and love this game as Mastermind - with color pegs instead of the numbers. The colorful version - Mastermind - was invented in 1970 by Mordecai Meirowitz, an Israeli postmaster and telecommunications expert. Apparently, his idea was at first turned down by many of the leading toy companies, but he persisted, and took it to the International Toy Fair at Nuremberg where a small English plastic company bought the IP rights and made it the most successful game of the 1970th. If you think something was sexist in the name "Bull and Cows", check out the peculiar original Mastermind box cover that called it a "Game of cunning and logic for two players:"

Since then over 55 million copies were sold in 80 countries. In US this game is made and distributed by Pressman Toys and is available on Amazon:

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Practice your logic skills with this Bulls and Cows, also known as Hit & Match game. Recommended for ages 10-100, parent assistant is advised for younger kids.
Can you guess a four digit number? It may be a secret military code or a treasure box key. All the digits in this secret number are different. For each of your guesses computer will tell you how many digits are perfectly matching the code (Match) and how many are in the code but in a different place than you guessed (Hit). Can you do it in less than 6 guesses? The game is created by Gilad Oved for TheMathMom. Find more of Gilad's games and MCAS math practice tests on his website http://www.gv-8.com/

Click to play: