patzer2: Positions like today's Tuesday puzzle (26....?) are excellent for teaching the rules of the game and basic tactics to beginners, with a conversation that might go as follows:
Teacher: Here's a position awaiting Black's 26th move from chessgames.com. What kind of forcing moves (checks or captures) are available to Black?
Student: He has two checks with capture (26...Nxf3+ and 26...Rxh3+) and two checks without capture (26...Bg1+ and 26...Rg2+).
Teacher: Very good! Now which of those captures most restrict the King's freedom (i.e. with the least number of free squares to move to afterwards)?
Student: The Rook checks (26...Rg2+ and 26...Rxf3+) leave the King at least two free squares, but the Bishop (26...Bg1+) and Knight checks (26...Nf3+) leave him only one free square.
Teacher: Excellent observation! So let's look at those restricting Bishop and Knight Checks. Which one of those checks allows us to follow-up with the other minor piece restricting check afterwards?
Student: With 26...Nxf3+ 27. Rxf3 the Black Bishop has no checks, but after 26...Bg1+ 27. Rxg1 Nxf3+ we get the one-two punch follow-up check.
Teacher: That's right! Now visualize the position after 26...Bg1+. Other than 27. Rxg1, what other choices does White have to get out of check?
Student: He can move the King after 26...Bg1+ to 27. Kh1.
Teacher: Good! Now can you visualize the position after 26...Bg1+ 27. Kh1?
Student: Yes! I see it's mate after 26...Bg1+ 27. Kh1 Rxh3#.
Teacher: That's right! Now why couldn't White play 26...Bg1+ 27. Nxg1?
Student: Because the Knight is pinned, and you can't move a pinned piece and expose your King to check.
Teacher: Correct! Capturing a checking piece is one way to get out of check, but pinned pieces protecting their King (a.k.a. absolute pins) can't move (let alone capture).
Now I want you to visualize the position after 26...Bg1+ 27. Rxg1 Nxf3+. Have you got it?
Student: Yes, I see it now. After 26...Bg1+ 27. Rxg1+ Nxf3+ the King is forced to play 28. Kh1 and now Black can play 28...Rh3#.
Teacher: Yes mate-in-two or three with the sham sacrifice of the Bishop! You've got it!
P.S.: Even though it's only a basic two and three move mate, the combination involves the decoy, deflection (removing the guard) and pin tactics.