In this post, we consider the Caro-Kann defense.
1. e2e4, c7c6.

2. d2d4, d7d5.

3. b1c3, d5e4.

4. c3e4, g8f6.

5. e4f6, e7f6.

The first games where the Caro-Kann defense was used, were played in Calcutta, 1856, by a mysterious Indian chess player named Somacarana against John Cochrane.
However, according to chess historian Edward Winter, this is not the earliest Caro-Kann. He mentions an 1845 game between unknown opponents from Edinburgh. The game may not look much like what we know as the Caro-Kann, but the first move nevertheless was 1...c7c6.
The Caro-Kann Defense, known for its extreme solidity and strategic, pawn-structured play, was named after English player Horatio Caro and Austrian player Marcus Kann, who analyzed the opening in 1886. Often nicknamed "the solid as a rock," it gained popularity in the 20th century as a reliable alternative to the French and Sicilian defenses.
For more info, see [3-6].
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References:
1. https://www.dynpass.online/tools/chess/start.html
3. https://www.youtube.com/watch?v=rmbU97iftC8
4. https://www.365chess.com/chess-openings/Caro-Kann-Defense
5. https://www.houseofstaunton.com/blogs/chess-openings/the-caro-kann-defense
6. https://www.youtube.com/watch?v=6N2b_xl7tpY