Wow! What a great post you gave us. Thankyou. It weems to me that you are on the right track. Doesn't it depend on how deep your opponent is in "book" openings plus how skilled he/she is at recognizing possbile "traps" and very skilled in tactics, etc? I have had much fun with the Two Knihgts Defense, Fried Liver version. Against weaker opponents or opponents not really familiar with the Fried Liver, I have a lot of fun. But against more experienced players, not so much. Isn't that the way it goes?
Please recommend me a viable BUT fun opening for white.
Against the Sicilian I like to play the Smith-Morra. Again, if they aren't real deep on this, I have some success. I play it anyway. I also try to play the same openings that I have learned, against white. Sometimes it works and sometimes, no. I have learned not to get frustrated when I lose but to go back and analyse the game and look for better responses to various positions in my games. Let us know if you come up with a good anser to your question. I'd like to see what others suggest. Have fun.............just have fun and keep playing!!

White opening that leads to open positions, early attacking chances, not so many variations...King's Gambit? I play it and it is exactly what you describe. It's still played at the highest level occasionally, too.
You wanted openings for black.....sorry....again, I experiment...the French is fun, to me, at least. I had a friend, yrs ago that taught me several versions of the french. He had a friend that was very strong at chess and specialized in the French.
You find the "queen's semi gambit" emotionally unfulfilling? I would suggest a modern benoni (she is a tough mistress, demanding careful attention and sacrifice from her practitioners, but if she returns your affection she is anything, but unfulfilling) except you seem to want to avoid theory.
I don't know how to answer you because everything played at a high level has accumulated a significant body of theory and you seem to only want one plan, to open the center and attack, despite your opponent's response, which is impossible.

Open the centre and attack?
Nope. The openings I play allows me to open up the queenside, which is different. Would you like me to share that?
Yeah, the question is unrealistic, but you can certainly get aggressive in the center and play attacking chess in a repertoire full of viable openings.
Just to give an example, if you stuck with 1.d4...
- against the QGD, you'd probably want to play the exchange, with a focus on opposite-side castling plans.
- against the QGA, you'd have 3.e4.
- against the Slav, you'd have the Geller (4.Nc3 dxc4 5.e4!?)
- against the Semi, you'd have the Botvinnik (theory intensive, but you can play for e4 and then just play chess till you feel more at home)
- against the Nimzo, you'd have the Samisch (a3 forces the exchange, then f3 soon to follow, preparing e4 when possible).
- against the Benoni, you'd have the Taimanov
- against the KID, you'd have almost anything. But why not play the 4 Pawns and ratchet the thinking up to its natural conclusion!
- against the Dutch, you'd have the Staunton. Maybe a little shaky, but still has high-level adherents, and certainly takes Dutchies out of their comfort zone!
The uniting principle being play traditionally, till an opportunity to get busy in the center presents itself (which usually happens pretty early on, since that was the point of 2.c4 in the first place), then seize the center and see what happens.

Yeah, the question is unrealistic, but you can certainly get aggressive in the center and play attacking chess in a repertoire full of viable openings.
Just to give an example, if you stuck with 1.d4...
- against the QGD, you'd probably want to play the exchange, with a focus on opposite-side castling plans.
- against the QGA, you'd have 3.e4.
- against the Slav, you'd have the Geller (4.Nc3 dxc4 5.e4!?)
- against the Semi, you'd have the Botvinnik (theory intensive, but you can play for e4 and then just play chess till you feel more at home)
- against the Nimzo, you'd have the Samisch (a3 forces the exchange, then f3 soon to follow, preparing e4 when possible).
- against the Benoni, you'd have the Taimanov
- against the KID, you'd have almost anything. But why not play the 4 Pawns and ratchet the thinking up to its natural conclusion!
- against the Dutch, you'd have the Staunton. Maybe a little shaky, but still has high-level adherents, and certainly takes Dutchies out of their comfort zone!
The uniting principle being play traditionally, till an opportunity to get busy in the center presents itself (which usually happens pretty early on, since that was the point of 2.c4 in the first place), then seize the center and see what happens.
You could also just play the Four Pawns against both the Benoni and the KID. Btw, what about the Grunfeld?
Yeah, the question is unrealistic, but you can certainly get aggressive in the center and play attacking chess in a repertoire full of viable openings.
Just to give an example, if you stuck with 1.d4...
- against the QGD, you'd probably want to play the exchange, with a focus on opposite-side castling plans.
- against the QGA, you'd have 3.e4.
- against the Slav, you'd have the Geller (4.Nc3 dxc4 5.e4!?)
- against the Semi, you'd have the Botvinnik (theory intensive, but you can play for e4 and then just play chess till you feel more at home)
- against the Nimzo, you'd have the Samisch (a3 forces the exchange, then f3 soon to follow, preparing e4 when possible).
- against the Benoni, you'd have the Taimanov
- against the KID, you'd have almost anything. But why not play the 4 Pawns and ratchet the thinking up to its natural conclusion!
- against the Dutch, you'd have the Staunton. Maybe a little shaky, but still has high-level adherents, and certainly takes Dutchies out of their comfort zone!
The uniting principle being play traditionally, till an opportunity to get busy in the center presents itself (which usually happens pretty early on, since that was the point of 2.c4 in the first place), then seize the center and see what happens.
You could also just play the Four Pawns against both the Benoni and the KID. Btw, what about the Grunfeld?
Yeah, I don't know. I hate the Grunfeld. I leave it to more sophisticated minds.
I've had some fun with the Polish opening for white. I rarely see it played. Although it is not the best of openings, it offers an element of surprise because it is a bit unconventional. You asked for "fun"...
I was going to recommend the Polish opening as well (1 b4). It's probably not best against perfect play, but at the below-Master level it's every bit as good as any other opening. It's fun to play, avoids a lot of theory, and gives you many opportunities to infuse it with your own creativity.

Yeah, the question is unrealistic, but you can certainly get aggressive in the center and play attacking chess in a repertoire full of viable openings.
Just to give an example, if you stuck with 1.d4...
- against the QGD, you'd probably want to play the exchange, with a focus on opposite-side castling plans.
- against the QGA, you'd have 3.e4.
- against the Slav, you'd have the Geller (4.Nc3 dxc4 5.e4!?)
- against the Semi, you'd have the Botvinnik (theory intensive, but you can play for e4 and then just play chess till you feel more at home)
- against the Nimzo, you'd have the Samisch (a3 forces the exchange, then f3 soon to follow, preparing e4 when possible).
- against the Benoni, you'd have the Taimanov
- against the KID, you'd have almost anything. But why not play the 4 Pawns and ratchet the thinking up to its natural conclusion!
- against the Dutch, you'd have the Staunton. Maybe a little shaky, but still has high-level adherents, and certainly takes Dutchies out of their comfort zone!
The uniting principle being play traditionally, till an opportunity to get busy in the center presents itself (which usually happens pretty early on, since that was the point of 2.c4 in the first place), then seize the center and see what happens.
You could also just play the Four Pawns against both the Benoni and the KID. Btw, what about the Grunfeld?
Yeah, I don't know. I hate the Grunfeld. I leave it to more sophisticated minds.
I'd probably recommend the Russian Variation (1.d4 Nf6 2.c4 g6 3.Nc3 d5 4.Nf3 Bg7 5.Qb3 dc 6.Qxc4 followed by e2-e4.)
Maybe even just the exchange. Build a big center, strongpoint the SOB, and voila, you're on move 10 of theory without actually having to think.
The downside of course being that there are still like fifteen moves worth of theory in several critical lines after that. But it fits in with the repertoire I'm recommending, which I freely acknowledge is way over my head.
I'd go for the BDG and the Tromp, if I were the OP.

Maybe even just the exchange. Build a big center, strongpoint the SOB, and voila, you're on move 10 of theory without actually having to think.
The downside of course being that there are still like fifteen moves worth of theory in several critical lines after that. But it fits in with the repertoire I'm recommending, which I freely acknowledge is way over my head.
I'd go for the BDG and the Tromp, if I were the OP.
Exchange Grunfeld : Meh...he said not thousands of theoretical variations
BDG : Meh...he said viable.
I'd agree with the Tromp and/or the Veresov.
Maybe even just the exchange. Build a big center, strongpoint the SOB, and voila, you're on move 10 of theory without actually having to think.
The downside of course being that there are still like fifteen moves worth of theory in several critical lines after that. But it fits in with the repertoire I'm recommending, which I freely acknowledge is way over my head.
I'd go for the BDG and the Tromp, if I were the OP.
Exchange Grunfeld : Meh...he said not thousands of theoretical variations
Certainly no worse than the Botvinnik, but the same principle applies. Know the idea, and you can get pretty far with it and just accept that the uber-booked can edge you out.
BDG : Meh...he said viable.
Which is why I didn't recommend it instead of all that other stuff, but it's still what I'd go for if I were the OP, since GM-viability is a nonsensical restriction for most people looking to build a repertoire.
I'd agree with the Tromp and/or the Veresov.
I also hate the Veresov, but that's neither here nor there.

King's Gambit is probably the most sound opening that does what you describe. Unfortunately, you need your opponent to respond with 1...e5, which they are not always willing to do. Still, if you're willing to develop a repertoire that will allow you to respond to all the various black defenses of 1.e4, the King's Gambit could figure in quite well. If you want to avoid lots of theory, you can use the Grand Prix attack against a Sicilian opponent (1.e4 c5 2. Nc3 intending Bc4/Bb5, f4, Nf3, 0-0, d3, Qe1, f5, etc).
Otherwise, the Polish is actually a viable try here. There's not a lot of theory to know (partly because your opponent won't know any, so lines will be useless, only the principles will matter). And as was said above, below master level, it doesn't really matter what you play.
If you play 1.e4, you're not going to like playing against the French, Caro-kann, or Pirc much, as you can't just attack those. The polish may actually be your best bet.
Try it out, and have fun!
Try the ponziani opening, its difficult to win with this opening but its fun, has many traps and its best for beginners coz its simple. According to bruce pandolfini its difficult to determine if this is the opening of the past or the future...lol

Gotta admit, those advertisers of the Ponziani sure have this site sewn up.
Instead, you may want to read what chess coaches on other sites recommend. The Scotch, Italian Game and Spanish all are recommended far more often than the Ponziani is by knowledgeable coaches.
Let me introduce myself.
I am a relatively inexperienced player (though I am somewhat familiar with some part of chess theory).
I have been looking for some time for chess opening for black, which is both fun and played at high level chess.
After experimenting with all kinds of sicillian, all of them which I didn't like (experienced opponents always managed to make a faster counterplay on the other side, or bust me open on my castled side), I settled on Scandinavian, which is one of the reasons I keep playing chess (as black at least).
I find it very versatile and open, as I really like open positions. I more or less know my game plan, and it does not really change much what my opponent plays early on ( except for few variations, mainly his d4, where I transpose to symetrical game, or after his e5 advance, where I answer with c5). All in all, three main lines.
Going back to topic of the post - is there an opening for white which doesn't really have a thousand variations like Sicillian has, depending on the opponent's response, which is open, very aggressive, and is played at high level chess?
I was very attracted to Lolli attack, but that isn't really an opening - it's a very rare variation based on very specific response from black. I do practice it from time to time, but forcing it seems very bad.
I tried queen's semi gambit, which I specialized in playing, but I find the opening not really emotionally fullfilling - it's a long grinding game on queen's side, trying to achieve incremental positional advantage which culminates in material advantage in the end game.
If any of you has a opening which really tries to bust open the position and attack the opponent early in the game please, do share, and perhaps your good and bad experience with it.
Thank you for reading this.