Puzzle of the week #145

Level: 
4-Rook
Chess Diagram: 

---r--k-
pb--qp--
-p----p-
-------p
-----Q-P
-B------
PP---PP-
--R---K-

Christmas is knocking on our door without snow in the city, but with the same warm feeling from childhood. Everyone is behaving nicer this time of the year; in chess winning a game is with mixed reactions: on one hand it is a nice extra gift beside those under the tree, while one the other hand you feel for the losing guy. I guess the best thing to do is solve a puzzle and not play a game; at least this way the losing side cannot be hurt :-)
Today you will enjoy a decent challenge, not too simple nor too complicated. Look at the diagram and decide:
a) What is the best way White should continue the play?
b) What key element have you used to answer the other question?

Total available points for this puzzle is 20. The answers will be published next week together with puzzle #146.

Puzzle #144 solution:
Game Paavilainen - Belkhodja, 1985 Facebook chess puzzle. Have received just 2 answers for this one; let's hope Santa is not going to read this while deciding your gifts... Frank is going to get something nice for sure; his answer is not the best solution, but at least it makes sense:
"I choose number a because White has a pawn that's free "a3" but Black has two that's free, "e6" and "f7". After Black promotes, it will be with check unless the Queen is protecting the King. Then we can trade off the Queen and it could be a win for Black. This should work for Black:
1... Rxd1+
2.Qxd1 Qe4+
3.Kg1 Qe3+
4.Kg2 Qxa3 0-1

Now that Black is a pawn up it can win easily by pushing all the pawns. At least one will promote. Then trade off the queens to let it be an easy win."

Meantime Jeffrey was convinced he should look for option "c"; unfortunately he stopped there, failing to finish a promising development.
The solution was quite simple if you noticed the following:
a) "f1" was a vital square White had to cover;
b) Black could occupy the 7th rank faster than suggested

Once we get passed that, the rest is simple trial and error:
1... Rd2!! What a beautiful move like a Christmas gift under the tree! Mate in 2 is a very direct threat (2... Qe4+ and 3... Qg2#), while Qb3 is stuck defending Rd1.
2.Re1 ... (only defence)
2... Re2!! This annoying Rook keeps on offering itself for the ultimate sacrifice. "Re1" must move away and "e4" is available for the mate in 2. The alternate of moving "Qb3" will give Black an extra option to use "d5" or "f3" if necessary.
a) 3.Qg3 Qe4+ wins the Rook and 0-1;
b) 3.Qb4 Qf3+ 4.Kg1 Qg2#;
c) 3.Qb7 ... defends the entire diagonal h1-a8, but also drops the Rook and the game;
Anything else is as hopeless as the above."

Correct solutions:
Jeffrey, Frank - 5 points

STANDINGS

Karl - 289 points
Jeffrey - 235 points
Rick - 174 points
Frank - 167 points
Alex - 111 points
Owen - 95 points
Edwin - 72 points
Nathaniel - 60 points

Comment: 

Achile's ankle (1)