The Bronstein-Larsen Variation is a dubious, but aggressive and double-edged way for black to fight in the Caro-Kann.
If you are interested in the basics of the Caro-Kann Defense check out this video on the opening principles, ideas and main variations: https://youtu.be/Jiz7KLKjLas
For a more solid alternative to the Bronstein-Larsen try the Karpov Variation (4…Nd7 instead of Nf6): https://youtu.be/YLEmufSFoGk
Despite being positionally unsound according to the engines, the Bronstein-Larsen Variation of the Caro-Kann offers great attacking chances when played properly and energetically. When humans are playing chess (especially people under 2300-2400) the fact that one side had + or – 0.5-0.9 in the opening means nothing. What matters is understanding the opening plans and ideas and knowing which squares your pieces should develop to, what’s your common attack plan and which side you are going to castle. Player who knows that can seldom have a disadvantage despite what the engines might say.
The Bronstein-Larsen Variation starts after the moves:
1. e4 c6
2. d4 d5
3. Nc3 dxe4
4. Nxe4 Nf6
5. Nxf6+ gxf6 – Black recaptures towards the center, weakening his king and doubling his pawns, but opening the g file to his advantage in exchange. Taking with the e pawn is the Korchnoi variation.