A QUEEN SACRIFICE

A QUEEN SAC:

Yep.. this is known as Legal's mate.

I don't want to rain on the parade, but 6.Nxe5 should lose to 6...Nxe5 instead of Bxd1.  You have to check this possibility carefully before trying for a Legal Mate. 

Just out of curiosity, 3.Bb5 followed by 4.Bc4 seems a bit odd 

6. Nxe5?? is indeed a blunder (one that I made one time, but never again)

I think every chess enthusiast, having learned the Legal pattern, immediately goes out and commits that same blunder. About half the time, the Legal mate works anyway!

i guess this is safer

Ruy Lopez Steinitz Variation is more popular than Semi-Italian Game so that's why.

"Ruy Lopez Steinitz Variation is more popular than Semi-Italian Game so that's why."

I don't understand that statement. If you wanted to be white in the Steinitz variation, why not continue 4.d4? If you want to play the Italian Game, why not play 3.Bc4? 3.Bb5 and 4.Bc4 looks like a pure tempo loss. 

It might be safer but only works as intended if Black blunders:

how to avoid it.

solve the puzzle as white

In the original game in #1, Black had already played g6, so he would never play Bh5. In #12, 5.Bxf3 avoids all the tricks, but White can certainly be satisfied with the opening

Semi-Italalian is WAY less common than Ruy Lopez Steinitz in my level and besides this trap can be pretty good.

Rc3+

yep

beginner's puzzle, please solve to unlock intermediate puzzle:

white to move

dxc6

intermediate's puzzle, please solve to unlock advanced puzzle:

black to move