The Most Dangerous Gambit
There are many gambit lines known in chess. Some of them are very sharp and dangerous, others are more positional and not even real gambits, like the Queen's Gambit. Today, I want to discuss one of the most dangerous gambits in chess, which you probably never heard about!
Before we start discussing this gambit, I would like to discuss something you won't find in any opening book. I call it POH (probability of happening). What is POH, and why is it so important? Let me give you an example. When I was a kid, I studied Boris Spassky's games and found the following gem:
I was like "Wow! This is exactly the opening I want to play! Where else can you get a crushing attack against your opponent's king right out of the opening, especially playing Black?" So, even though I had been a Sicilian player my whole life, I was ready to switch to 1...e5 for the sake of the Marshall Attack employed by Spassky.
And suddenly I encountered a problem. There were way too many deviations my opponent could use on the way to my target position. Here is a brief list of them: The King's Gambit, the Central Game, the Vienna Game, the Danish Gambit, the Bishop Opening, the Four Knights opening, the Italian game, and I am not even listing very uncommon openings like the Ponziani.
Moreover, even if my opponent decides to play the Ruy Lopez, there are about a dozen deviations right there, like the Exchange Variation and others. Therefore, I quickly realized that in order to switch from 1...c5 to 1...e5 to play the Marshall Attack, I needed to study about two dozen different openings and variations.
Worst of all, due to the variety of the available options, the POH of my target position in my games was no more than 10%. Did it make any sense to do this humongous amount of work for something that might happen in only about 10% of my games? That's why I never played the Marshall. 
I know, the introduction is getting too long, so without further ado, let me introduce the main topic of today's discussion: the Urusov Gambit!
It can happen through different move orders:
Or:
But the move order I would recommend is this:
Why this move order? It is all about the POH! After the moves 1.e4 e5, which are the most common in scholastic and club competitions, White plays 2.Bc4. Now, if you look at Chess.com's database, you'll see that 2...Nf6 is by far the most popular move. It has been played 10,497 times vs. a distant second 2...Nc6, which was played 2,193 times. Then after 3.d4, the move 3...exd4, which is the best, was played 563 times, vs. the second 3...Nc6 (only 55 times). So, long story short, I expect the POH for the Urusov Gambit to be somewhere around 70%! I know it might sound like this:
So instead of talking about statistics, let's do some chess analysis.
As I mentioned before, the Urusov Gambit is the most dangerous one, because in our target position, Black has only three moves, and two of them pretty much lose! So, this is already a 66.6% success rate for you. Oops, statistics again, sorry.
Let's see how it works:
1) 5...Nd6?? is the absolute worst of these three options since after 6.0-0, the threat Re1+ will quickly decide the game:
If Black blocks the check with his b8-knight, it saves the g7-pawn but loses the game anyway:
2) 5...Nc5 is a better move, but still leads to a difficult position:
Even Mark Taimanov, who later became a super grandmaster, was not able to save his position after this dubious move:
3) 5...Nf6 is the best move, as it allows Blacks to finish their development. Nevertheless, White castles long and will have a strong attack regardless of whether Black castles or keeps his king in the center. Note that there's a very powerful idea that ensures a strong attack if Black castles short: White can move their queen to h4 and their bishop to d3. The threat to the h7-pawn will provoke the move h7-h6, after which a typical Bxh6 sacrifice will decide the game. Here are some examples:
Now, when you know the basic ideas of this powerful weapon, some of you might ask: "So, can I beat a grandmaster with this gambit?" Well, as I mentioned earlier, the best results with this opening will be achieved in scholastic and club events. But if you play a grandmaster in a simul, you might get your first GM scalp. At least in the following game played in a simul, White managed to beat World Champion Emanuel Lasker!
Give this exciting opening a try, and make sure you share your brilliancies in comments!
