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Now the text combination 22 Qh6+ Kf7 23 Bg6+ Ke7 24 Qg7+ does not work because black's queen now covers g7.

<computer chess guy: Rybka 3 will play Nf6+, given enough time (switches from 13. a3 at depth 16).> Fritz 12 on my 2.1 GHZ dual core processor also struggled with this one. It wasn't until over 10 minutes of calculation at 18/47 depth that Fritz switched from 13. a3 to 13. Nf6+ as it's first choice.

Even after 20 depth, the best Fritz could find was 13. Nf6+ gxf6 14. gxf6 Bxf6 15. Qxf6 Qxf6 16. Rxf6 Nd7 which leaves Black with a strong and likely winning advantage.

give about turn you get the feel light will run out of the steam f6 to the middle of nowhere bus wire in call at h7 it sense in fang tooth queen h6

to join the party ramble give do it book in a slot low ar hum prime whip and whim free vigour deems bit ok love h7 down hard it ardent in act

up e4 mind for one god snare victor horse f6

fetch quench safe got ide a tid bit ooh in flight am pack in fad a delve spark our each toe ever

pluck at cad infer tile ground in fly cushion g8 has been sprung aim gash relax het up e4 in f6 fad to fit ok in ogles son slide capoffit a link

again strain arm give delve in dug bishop bemoans lack of room aka slow burn dock of the bay h7 comes next in line open it now in royal subject g8 as type for facet f6 in am h7 got bishop hickory backs later g6 dukes a dickory dock i think kind band have horse f6 ar a dish rag e4 up ride a lion in jail a f6 ay etc e4 has to come first am ply am d3 routes h7 at next stand and black has ive a totally demolished dukeside arm

belly foiled front foot first fancy another bite of the cake freer frame in picture vow at back it reinstate sugar field cane bamboo h7 bishop flashy fog-horn finish foot fan take down front flaps f6 flint stone in d3 terrific double break through bishop enough to a gog hoof rough to form an opinion where black went wrong borough to finish ave in flush f6 agile leap at fat chance h7 as brother bind i spot spark flinch fang tooth queen follow in got the knack f6 cannon h7 fodder a toe in poke down if ive this right in d3 ignoble truth baby am h7 route one a pan 13...gxf6 14.Bxh7+ effect heaters shoot up a f1

to suck the blood dry from the pos up have spark effront it fetch in feels and feeds again free lance fester a lunge f6 rook as put in remembers burning effigy h7 rates head in hop scotch h7 a duke steps up erm cant take back h5 in the by lane heeds the word as h7 court a horded approach in elevate g8 hassles hut-off cut down by two swathes am higgedly piggledy bishop arm as hirsute am tailor h7 guild the lily as mind g7 up ply in light upper wary as sever to hunches abound run in to hangers and feed mug to hold line low good as no rag to hush hog ghost a key in duke g7 pour h5 on scorn and prise upon arm h4

to gain a fat heave f6 and rook seem a f6 take down press at all chances a gush to give hunters and hunted gives me the heebee geebees as early as a3 thirteenth up a fob off rook as park the bus in front candy black bags some brief f6 call only to be up routes again f6 let d4 am go buster d8 and alf e7 both sight act d4 like ellucidate drawn over hot coals the kabbalah ley line h5 after glides g7 note dont baulk at shag pile up ride g7 bags a spot in the sun towel f6 thrown in jam d4 keeps to plug arm h4 enter riff i see hogs around a tile show gun i baste again f6 i rade 14...Kg7 15.Qh5 fxg5 16.c3 Nd5 or a chests 16...Nd7 both amount to the same roughly speak

winks a line f6 take down dipsarch bishop spread prefer to give back tongue

snake material eagle f7 lets fly am search for truth am bottle bog 20.cxd4 Qxd4+ for duty honour in hope the great and god a duke up a g2 aint half bad am f1 also staff fly off the handle both alright to win forge the path indeed rake over hot dead coals am bounty hunter did flake give arm d4 strung up a fish around for ergo a coast dead ducky oh to protocol climb the highest mountain as carry a g7 aint sitting pretty ramble give but it's no sacrifice as we all know ledge off re you came light ride bogged down safari g6 as stoke a fire culpa dids one up eh i 21.Kg2 f6 22.Qh6+ puppy hush am rock over the place horde in hammer centre chase is on to flush him out into hot head h4 as watch over h5 and h6 a bevel oh drome d6 us again ram in a tour as put act i see can f7 survive furnace burns around the fire stoke hinch a lift as computational l0 win from here on in trust a key hffg huffle and shuffle strapped up hog off f7 a good clean finish am

rock see a rib to go 22...Kf7 23.Bg6+
in be proof at stage giveof arm etc all laid down

a bed i gutoff bishop retreat monarchs try to flee give sparse lock eg drink inside rim around e7 rig you're hopeful crums now indeed i wall of guv sound celebrated in forced him out to d6 after glide h6 alter exactly one for cross oh sore point us call a loose duke dances e7 i ment cough up a rook by the looks of it ok in fan dangled glove open inch on durable as ever piggy rates call i wag in banka gg at hoofed go figure at got 23...Ke7 24.Qg7+ am band give spark a glorify oh door it book in if the penny drops black is gonna have to find himself a piece down but carry in on he thinks I'll be the judge of that squawk g7 a parrot flies in for the coup de grace d6 or chest d8 whence gaggles around has as have in blood calls for the cut swathe g7 queen and padre ghosts bishop back door as put in flog a dead donkey a gog goofball waiting for ive cuffed his demise at rise above final good push alarm in row blow him off at dead 24...Kd6 25.Qxf8+ indeed it revver dictum bless a drive at iffy rail as whites la ship it hind maneovre in

Black threatens 13... Nxd3 and 13... Qxd4+.

It is not clear whether White can mobilize the remaining forces after the more or less prosaic 13.Nf6+ gxf6 (13... Kh8 14.Nxh7 Nxd3 15.Nxf8 wins the exchange due 16.Qh5+ and mate in two) 14.Bxh7+:

A) 14... Kxh7 15.Qh5+

A.1) 15... Kg8 16.g6 Qxd4+ 17.Rf2 fxg6 18.Qxg6+ Kh8 19.Qh5+ (to control the escape square f7) 19... Kg8 20.Bh6 looks winning due to the threats 21.Qg6+ Kh8 22.Qg7#, 21.c3, etc.

A.2) 15... Kg7 16.Qh6+ Kg8 17.gxf6 Bxf6 (17... Qxd4+ 18.Be3 + -) 18.Rxf6 followed by Rf4 and Rg(h)4.

B) 14... Kg7 15.Qh5

B.1) 15... Rh8 16.Qh6#.

B.2) 15... Qxd4+ 16.Kh2 Bd6+ 17.Kg2 fxg5 18.Bxg5 looks bad for Black.

B.3) 15... fxg5 16.c3 unclear.

C) 14... Kh8 15.Qh5 Qxd4+ 16.Kh1 seems to win (16... Qd5+ 17.Be4+ Kg7(8) 18.Qh7#; 16... Kg7 17.Qh6+ and mate in two).

My first idea was 22.Bf4, trying to divert the black queen, stopping ... Qg4+ and freing the path for the QR, but I not sure whether Black can achieve perpetual.

The bishop is tabu due to 22... Qxf4 23.Qh6+ Kf7 24.g6+ Ke7 25.Qxf4.>

OK. That's a good start. Now you (anyone) after 21...f5?! 22 Bf4!? have to respond to both 22...Nd7 and the more onerous looking 22...Qxb2+, below.

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Come to think of it, you also have to explain why can't white ignore 22 Bf4 and just play 22 Qh6+ directly.

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Rybka 4.1 x64:

OK. That's a good start. Now you (anyone) after 21...f5?! 22 Bf4!? have to respond to both 22...Nd7 and the more onerous looking 22...Qxb2+, below.>

In the case of 22... Nd7 23.Rd1 looks crushing

A) 23... Qxd1 24.Qxd1 Kxh7 25.Qxd7+ wins.

B) 23... Qxb2+ 24.Rd2 Qxd2+ (else 25.Rxd7+) 25.Bxd2 with a more or less balanced material but keeping a winning attack.

In the case of 22... Qxb2+ 23.Kg3

A) 23... Qxa1 24.Qh6+ Kf7 25.Bg6+ Ke7 26.Qh7+ and mate soon.

B) 23... Nd7 24.Rd1 Qc3+ 25.Kh4 Rfd8 26.Qh6+ and mate soon.

C) 23... e5 24.Qh6+ Kf7 25.Qf6+ Ke8 26.Qe6+ Kd8 27.Rd1+ Kc7 28.Bxe5+ wins the queen.

<Come to think of it, you also have to explain why can't white ignore 22 Bf4 and just play 22 Qh6+ directly.>

Actually, I think 22.Qh6+ also wins by pushing the g-pawn, 22... Kf7 23.g6+:

A) 23... Ke7 24.Bg5+ Kd7 25.Rd1 Qxd1 26.Qg7+ wins the rook with check and eventually leaves Black defenseless against the promotion of the g-pawn.

A) 23... Ke7 24.Bg5+ Kd7 25.Rd1 Qxd1 26.Qg7+ wins the rook with check and eventually leaves Black defenseless against the promotion of the g-pawn.>

I completely missed 24 Bg5+ in this line. I thought that the position was a dead draw. Like you said, you end up with something like this with black to move.

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Haha! Good one, but not quite. However, they were from rather 1954, 1984, 2004 or 2014. See the trend?>