Amazing Opening Trick Against Scandinavian Defense(Tennison Gambit)

I agree. But sometimes there arise questions about "applicability" of this or that line. Saying at once, the numeric evaluations of the strong engines are taken just for reference, without relying much on them. Anyhow, if a very strong engine, with the time control 40 moves/40 hours, say, in the position of the Schliemann gambit (or Jaenisch gambit) from the Ruy Lopez - 1.e4 e5 2.Nf3 Nc6 3.Bb5 f5, after about 1.5 hour "thinking time" at the depth 40, the engine makes the move 4.d3 showing +0.37 (4.Nc3 +0.33) in White's favor - and we all know at what level 3. ... f5 is played (I mean, over 2700, and even over 2800). The evaluation of the same engine with the same time control of 40 moves/40 hours - the King's Gambit 1.e4 e5 2.f4 (-0.29); the Sicilian Wing Gambit 1.e4 c5 2.b4 (-0.26); Evans Gambit 1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.b4 (-0.26) (just for reference, Garry Kasparov as White crushed Vishy Anand in the Evans Gambit); the discussed Tennison Gambit from the Scandinavian defense 1.e4 d5 2.Nf3 (-0.26).

Saying again - the numeric evaluations are just for reference, they are relevant (and for illustrative purposes taken of the same strong engine with the same time control). Just a funny thing - the Schliemann gambit from the Ruy Lopez is considered as correct, whereas the Sicilian Wing Gambit - next to "refuted", and I would not be surprised if a 2700-2800+ chess player said "The Tenisson gambit is incorrect/refuted" (just because it is not used at the high level), whereas the Schliemann gambit is "quite correct and quite playable" (just because they do apply it at the high level)  That is all just thoughts, nothing to be taken seriously.

We should remember that it's all down to the availability of tactics to support the continuation. I doubt the Sicilian W.G. has been looked at with the depth and intensity that the Schliemann has. Furthermore, there are in general more immediate tactics available in double k-pawn openings. My impression is that there's nearly enough compen for the pawn and it's therefore round about equal. There are people who have worked out quite complex systems based on the W.G. and I certainly take it seriously.

However, the Tenisson is merely a way to allow black to play 1. e4 ...d5 with impunity. There isn't enough development for it to be a worthwhile attempt for white ... therefore it's just a cheap trick and everyone should know, from either side, the potentiality of the Qe2 (or Qe7) to check and cause disruption ... it's a well-known theme. An opening based on a trap is exclusively for 1600 minuses.

Here is an example, I played the 5' blitz game at the playchess.com, shortly after I began working on the Sicilian Wing Gambit, in 2009. Once it happened so that the opponent was a GM (of course this trapping variation occurred in many other games against significantly weaker opponents, too)

Sorry about an off-topic example, just wanted to say that not only those variations are good and interesting which are played often ... (The Berlin defense in Ruy Lopez is played rather often, but maybe I am mistaken something when I many times read in the comments the disappointment of the viewers who are watching a live game of some tournament or a match when the players choose the Berlin defense ...............) But of course it's players' right (not viewers' right) to choose a dull or not a dull variation for other to watch during a live game 

There's a slightly related gambit that goes 1. Nf3 ...f5 2. e4 that has a lot more merit because here, white's development is already better than black's. The gambit is in fact so strong that it makes 1.Nf3 ...f5 at least dubious. I played it in otb slowplay about half a dozen times without knowing much about it at all and I did ok, because it''s basically well-merited.

Black's move 3, although good, already had me worried about the queenside light squares. Experienced players will immediately be aware of what Qe2 threatens, and play a natural move like 5...Nc6.

You know, my implression about the 1.Nf3 f5 2.e4 ("Lisitsyn Gambit") goes far back to the past, when in about 2001 or 2002 I made a short match of 4 games between the Chessmaster 5500 and Chessmaster 8000. In one of the games, the 5500 chose 1.Nf3, and since that was the period when I rather often practiced the Dutch defense as Black, it was interesting for me to watch how the engines play it between themselves  Of course, upon 1.Nf3 I entered the move 1. ... f5 for Black and let them play on. The Chessmaster 5500 played 2.e4, and it was a really exciting game to watch, Black won (unfortunately I would not able to find that game any more, the games were stored on paper in the copybooks, not in the computers as it is now ... ;)

As for the Scandinavian defense, just several days ago in some topic I wrote in the comments to some game - "If White wants to create problems for Black after 2.ed Qxd5 - he must play 3.Nc3" 

I think that's a fair assessment. Let Black choose from the three normal variations.

Just out of curiosity, not long ago I wondered if White has at all any alternative to (1.e4 d5) 2.ed - oooops) The same concerns here - If White wants to create problems for Black - 2.ed goes without saying, indeed.

And as for the normal Scandinavian position after 2.ed Qxd5 3.Nc3 - I like 3.Nf3 upon all the three of them - 3. ... Qa5 4.Nf3, 3. ... Qd6 4.Nf3 and 3. ... Qd8 4.Nf3 (another surprise for me was that 2. ... Qxd5 and 2. ... Nf6 are completely equal in strength, just the matter of taste). When analyzing the Scandinavian, the strong engines showed me, to my surprise, that 1. ... d5 is better than its reputation, and I also understood that if White does want to create at least some problems for Black in the Scandinavian defense - he should be very accurate with what he plays, otherwise Black equalizes very easily

Maybe black can reply with 3...f5. Then white has a lot of attacking moves such as Bc4,Qh5+.... But none of this leads to mate or loss of material neither does it gain the sacrificed pawn. I beleive black will have a strong pawn centre and a few extra moves for it's minor pieces to develop.

Join the 3...Qd6 or the 2...Nf6 Scandinavian Club at Chess.com. These are probably the most active clubs for this Defense. 

I'm certainly the stupidest player who can't win despite the queen lead, and since I'm so much of a moron I can't be bothered to see how to insert a game properly on a forum for the needed details. Someone shoot me.

Why didn't you get your pieces into the game?

Because he is certainly the stupidest player who can't win despite the queen lead, and since he is so much of a moron he can't be bothered to see how to insert a game properly on a forum for the needed details. Someone shoot him.

the tennison is REALLY busted when black knows his theory. it's a cute surprise weapon I used to play myself, even buying that lousy book that literally fell apart at the seams long ago, but is easy to play against if you know what you're doing. I'm sure a lot of black players are booking up on it as it's getting popular. I've seen it a good 50 times, but NO ONE plays the stronger blackmar diemer gambit. the flip side of that is that scandinavian players are either really creative or bookish like sicilians because I was getting crushed trying to play the 3.Nc3 main line BDG against them, and I know they NEVER see 2.d4!?

I posted a main line theory tree here where black is doing good in pretty much every line