Wednesday, 25 August 2021

Introducing the Candidates

Over the weekend, JannLee & daughter Bella made the draw for pairings in the 2021 Crazyhouse Candidates and together with Zaraza, IgorBugMate and MarlonC streamed the following introduction video to the Candidates:

The following are the descriptions of the Candidates in their own words followed by creative descriptions by Zaraza in English and Russian (translated thanks to MarlonC):

You can see the latest standings for the 2021 Candidates here.

Monday, 9 August 2021

Introduction to Crazyhouse 960

Season 9.60

The first three weeks of July saw four teams of seven as well as back-up alternates battle it out in the second ever full crazyhouse 960 league. The winning team was Red Button made up of Fumitoks on board 1, terra87 on board 2, grogers, IgorBugMate, Zaraza, the_Crocodile_Hunter & Zher0. The team went unbeaten in the league with an impressive 69.0% game win rate. Second & third were the unimaginatively named Team 2 & Team 3 led by LegionDestroyer & Kleerkast respectively, while Dirty Diagonals despite great team spirit came in fourth. Special mention goes to Fumitoks & terra87 who both went through the league undefeated with 6 wins out of 6. We take this opportunity to introduce crazyhouse 960 through highlights from this recently completed league.

How to Play

Go to, click login on the top right, then authenticate and it will automatically recognise your lichess username (if it doesn't work, repeat in incognito browser). Like lichess, you might also wish to press the settings button right of your username, then Background: Dark to get the familiar dark background that’s easier on the eyes. You can create challenges in the lobby or train with Fairy-Stockfish, building up from Level 1 to Level 8. Currently, there is a 30 second delay on move 1 before the game times out. During this time, you can assess the unfamiliar position and decide your first move. 

To castle, like in 960, you need to drag king over rook at a time when the king hasn’t moved, is not in check, and none of the squares it passes through are in check. Just like crazyhouse, the game is super-powered chess, rich in tactical combinations and requiring good understanding of short-term positional weaknesses. Basic chess principles apply. Let’s start with beginner principles and increase in difficulty to master this game! Along the way, we present 50 puzzles and one outstanding highlight game of the league.

1. Activate Pieces

This means activating the pieces on the first rank at the start of the game, but also activating the pieces in hand to maximise their contribution. Since your opponent also wants to activate their pieces, it also means trying to restrict the scope of your opponent’s pieces.

Bishops can begin to develop by simply opening the lines. Knights however need to be moved. Pushing a central rook pawn, or a pawn that develops both a bishop and the queen, or a pawn that opens a long diagonal are good candidate first moves, or also a knight in the corner.

A knight in the corner has only one square to move to, so it is usually wise to develop it quickly and not put a pawn or another knight there.

Make sure not to leave your most powerful piece, the queen, buried in its starting position for the whole game. But equally, when you do develop the queen, make sure to develop it with threats which cannot be ignored and cannot be parried with a counter-threat on the queen. It must have “places to go, things to do!” Do not be afraid to sac it.

2. Don’t Hang Mate in 1

One of the biggest differences as players get stronger is that they do not give up, even if completely losing. they make it hard for the opponent to find the mating sequence, and in particular they do not hang mate in 1. They prolong the game for another move and another move and in crazyhouse comebacks can and do happen! Conversely, if the opponent does hang mate, make sure you deliver it!

3. Spot Hanging Material

This is simple enough. Unless there is a very good reason not to, take free material! Conversely, don’t leave material hanging. Every pawn you lose, not only are you a pawn less, but your opponent has a pawn more in hand to use back at you later in the game.

4. Piece Values & Piece Sacs

Like in crazyhouse, knights, bishops & rooks are similar in value. This is because unlike chess, there is no endgame and it is in the endgame in standard chess when rooks begin to dominate because knights have short range and bishops are restricted forever to one colour complex.

Knights have most value in delivering checks that can’t be blocked so they can initiate fast attacks opening up the opponent king.

The greatest value of Bishops is that they can attack & defend at the same time. They can also take and defend backwards!

Rooks can sometimes be used on a file to both attack & defend, or sometimes to purely attack on the opponent’s back rank, and sometimes to purely defend on one’s own back rank.

All minor pieces are worth approximately two pawns. The greater value of pawns compared to standard chess is because after all, pawns can be dropped on the sixth or seventh rank where they threaten the opponent king or even threaten to promote to a Queen or Knight. Note that a promoted piece once captured reverts to being a pawn in the hand of your opponent so it is especially easy to sac it for material & initiative.

Pawns are invaluable in defence, but often you should keep your last pawn in hand for your attack. A single pawn in hand is sometimes enough to spark a mating attack on the opponent’s king.

Queens are worth two minor pieces in crazyhouse. They are of course the strongest piece, but for precisely this reason they are also a liability. A lot of time and initiative can be lost if our opponent develops and drops pieces attacking our Queen, so we must sometimes be willing to sac it.

Two thematic piece sacs are the sac that demolishes the opponent centre and the sac that demolishes the opponent’s king. If this picks up two pawns for a minor piece, then given the above piece values one could argue that it isn’t a sac at all.

Piece sacs are especially powerful on what JoannaTries has termed “tender pawns” which are pawns defended only by the opponent’s king. In standard crazyhouse, f2 & f7 are tender squares defended only by the king, while c2 & c7 are potentially weak squares if the pawns are moves as they are defended only by the Queen. 

Given a fresh 960 position, it is instructive to consider what are the tender squares corresponding to f2/f7 in this fresh position. If the king is castled, then as in standard crazyhouse, g2/g7 are often tender pawns.

5. Colour Complexes

As expounded in mastertan’s classic guide on light & dark squares in crazyhouse, one has to be aware of the colour of squares on which it is most profitable to attack and conversely how best to defend. The piece sacs from the previous chapter often help initiate an attack on a colour complex. But sometimes, a beginning player unwittingly opens up a colour complex without provocation and allows one to take advantage of the resulting weak squares.

6. Basic Mating Patterns

If we can deliver mate, it is important to find it and not to let the game slip away in complications. Players often have an intuition there might be a mate, and if you get this feeling it is often worth spend some extra time calculating to find it, or to find what piece you need for it. In slow crazyhouse, it is worthwhile playing obvious moves relatively quickly and leaving at least a couple of minutes of your time for critical positions to find the fatal blow.

6.1 Back-Rank Mate

Along with 6.2 Smothered Mate, back-rank mate is one of the most important mating themes for the beginning crazyhouse player to be acquainted with. You can find a full introduction to back-rank mates in crazyhouse with both lichess practice study, solution study as well as embedded video on this blog, as well as a follow-up second video & second study made subsequently. The main idea is that diagonals and especially pawns on the 7th rank can be the catalyst for a back-rank attack because with a single rook and enough pawns the opponent's back rank rooks can be recycled into one's own pocket and dropped again, clearing them all away!

6.2 Smothered Mate

In crazyhouse 960, one must be especially aware of undefended pawns, or pawns defended with only one piece so if that piece is moved, this pawn or square becomes undefended. This can give rise to smothered mates & smother tactics (about which more in the next section). There are also the classic smothered mate patterns as in standard crazyhouse.

6.3 Magnet Mate

The idea of a magnet mate is to drop a checking piece adjacent to the king which acts as a magnet forcing the king to take and in so doing drawing the king to an unsafe square where it can be checked & mated more easily, sometimes because it allows us to pick up more material with check.

6.4 Double-Take Mate

Sometimes the checking square is defended so at first glance the opponent king is safe. But if we look deeper, we notice that we can re-capture the defending piece with check! This provides the opportunity for a double-take mate!

6.5 Knight Drop Mates

Knights are the one piece whose checks can’t be blocked, so sometimes they can be used to draw the king out of safety. See if you can calculate these positions all the way to mate.

6.6 Cover Escape Mates

A useful mating technique is to examine the path the king might run to safety and delivering checks which also block this path! This keeps the king in a box and mating much easier.

7. Smother Tactics

The threat of smothers can lead to some interesting tactics in the opening. This is the only position in this blog not taken from a league game, but from my first ever game of crazyhouse 960 four years ago with andreijl in a lichess study, and we both missed it!

8. King Safety

The possibility of castling can sometimes rapidly evacuate the king from an approaching attack. 

Usually, the best way of keeping the king safe is by moving and dropping one’s pieces around it, defending the checking squares. If in check, it is often best to try to run the king to squares where it cannot be checked again.

In rare cases, the best approach is to create luft for the king so it has safe passage to run.

9. Drop Attacks

9.1  Pawn Drops on the 6th

The most common drop attacks are pawn drops on the 6th corresponding to @h3/@h6 in standard crazyhouse. A single pawn in hand can be the spark that triggers a bonfire on the opponent’s king.

9.2  Pawn Drops on the 7th

Another common attack in crazyhouse are pawn drops on the 7th, either threatening to promote or as we saw already in 6.(i) to put a major on the back rank and launch a back rank attack.

9.3 More Advanced Drop Attacks

Sometimes piece & pawn drops can come with more complex clearance ideas which lead to unstoppable mating attacks.

10. Pawn Forks

Often in crazyhouse 960, knights develop to squares two apart and are prone to pawn forks so one must keep an eye out for this.

One must also be wary of pawn drop attacks on the 7th winning material.

11. Dangerous Diagonals

12. Advanced Mating Technique

12.1 Clearance Mates

Clearance mates involve clearing away opponent pieces to open squares or lines.

12.2 Castaway Mates

Castaway mates involve discarding one’s own pieces to open up squares to deliver mate.

How to defend and why?

12.3 Interference Mates

How to interfere with the defence of the rook on b1?

12.4 Block-Escape Mates

Q@h4!! What is Black’s follow-up after Kxh4?

Solution Key

1. Activate Pieces


developing the Queen and threatening the undefended g2 pawn


defending & developing with a double counter-attack


keeping the bishop diagonal open


limiting the scope of the opponent’s Queen. Black’s best move is Qxg3.

2. Don’t Hang Mate in 1

B@d2, N@c6, R@b6, R@e1

3. Spot Hanging Material




threatening N@f2+ forking king & queen


double-check & mate, which is much better than taking free material! 

(Trick Question)

4. Piece Values & Piece Sacs

Nxd5! cxd5 Qxd5

White has two pawns for the piece & has demolished Black’s centre. Black’s king is next!

Nxb7! Nxb7 @a6!

with two more pawns in hand, another will soon be landing on b7

Nxg2! Kxg2?? Nf4+!

With another knight in hand, White would soon be mated.

Nxc7! Kxc7 Qa5+!!

Not only is Black’s king safety wrecked but White wins back the lost knight after Qxa7

5. Colour Complexes

N@f3! Ke2 Nxg1! Ke1 Nf3 Ke2 Nxh2

6.1 Back-Rank Mates

@f7 Kh8 R@g8 Rxg8 fxg8=Q Kxg8 B@f7 Qxf7 (Kf8/Kh8 R@g8#) Qxf7 Kxf7

Notice how we recycled Black’s rook and queen back into our own pocket with initiative, so we can drop them back first! 

The finish is now simple — there are mates one move faster, but we like:

N@e5 Kf6 Q@f7 Kg5 Qf4 Kh5 Qh4#

6.2 Smothered Mates


Oops! Have to watch for this is crazyhouse 960!

N@h6 Kh8 (gxh6 Q@h8#) Q@g8 Rxg8 Nxf7#

The classic pattern!

6.3 Magnet Mates

R@g8 Kxg8 B@f7 Kxf7 (Kxf8 Q@e8#) Q@e6 Kxf8 R@g8#

There were other mates e.g. starting with Nxg6, but this way was fastest.

R@a1 Kxa1 NxQc2 Kb1 Na3! Ka1 Q@b1! Rxb1 Nc2 

Combining the magnet and smothered mating themes!

After Kb1, there is also Q@a1 Kc2 Qxb2 Kxd3 Qd4 and if Kc2, B@d3 Kc1 @b2#, so: 

Ke2 B@d3/@d3+ Ke1 and the key move Qe3!! (exploiting the pin) followed by Qxe2#

6.4 Double-Take Mates

R@f8 Qxf8 Rxf8 Kxf8 Q@f7#/Q@g8#

Q@g8 Rxg8 Qxg8#

Bxh7 Kh8 N@g6 fxg6 Nxg6#

6.5 Knight-Drop Mates

N@a3 bxa3 N@c3 Kb2 Bxa3 Kxa3 @b4 Kb2 @a3

N@a3 Nxa3 (bxa3 Qxa1#) N@d2 Bxd2 Qxb2#

Notice that the order matters, as N@d2 Bxd2 first gives the King luft on c1.

6.6 Cover-Escape Mates

@c6! (blocking d7) Kc8 @d7! (blocking e8) Kd8/Kb8 @c7#

A mating square of pawns on the 6th & 7th ranks!

7. Smother Tactics

Bxf6 gxf6 (exf6?? N@e7#) N@h6 Kg7 Nf5 Kg8/Kg6 Nxe7 Kg7 NxQc8

8. King Safety



This both provides luft for the King on b1 and threatens mate with:

Qg8 Kg6 N@h8 Kh6 N@f7 Kh5 Qh7 R@h6 (else Qg6#) QxRh6 gxh6 R@h4#

Qg8 Kh6 is no better e.g. @g5 Kxg5 Qxg7 R@g6 N@h7 Kh5 N@f6 Rxf6 Nxf6#

9.1 Pawn Drops on the 6th



Nxf3 Nxf3 @h3 gxh3 Bxh3 @g2 Bxg2 Kxg2 @h3!!

Black has enough pawns in hand to not need to prepare with @g4

9.2 Pawn Drops on the 7th

@d2 Kd1 @e2 Kxe2 Qxd3 Kf2 (Kd1 @e2#) N@h1#

9.3 More Advanced Drop Attacks


This is the best but not the only move and it is crushing!

There are too many lines to go into them all. Click through to the study!

N@h3 gxh3 B@f3 @g2 BxNe2

Material is unchanged but the White knight on e2 is replaced by a Black bishop.

10. Pawn Forks





Trick Question! Not @e7, else 

Qxg2 Kxg2 N@h4 Kg3 N@f5 Kh2 Nf3 Kh1 @g2 Kxg2 N5h4 Kf1 B@g2 Ke2 Nd4++#

@h7 Kxh7 B@e4 is not better as the Black king is actually safer on h7

12.1 Clearance Mates

Nxc3 bxc3 Q@b3#

@e6!! fxe6 QxNe8!! Rxe8 N@d6 Kf6 (Kf8 N@d7 Kg8 @f7) e5 Kg6 @h5 Kh6 Nf7#

or if after Qxe8 Kxe8 N@d6!! exd6 R@e7 Kd8 Rad7 Kc8 N@a7 Kb8 Nxc6 Ka8 @b7#

@e3!! NxRg2 (dxe3?? R@g1# no blockers!) R@g1 R@f1 Rxf1 Kxf1 R@h1 R@g1 @e2 Ke1 Rxg1#

@e3 whether taken or not covers the d2 square restricting the White king to the back rank

12.2 Castaway Mates

Qxf1 Nxf1 then Nf2!! @g4 & R@h5 before, between or after is mate!

Qxf6!! gxf6 Nf5 Kd7 B@c6


If instead Kd1 Rxd2 Ke1 Re2 Kd1 Re1!! Kxe1 @d2 Kxd2 B@c3 Kd1 Bxf3 @e2 B1xe2#)

Nxe2 second-time round doesn’t work because of:

@d2 Kxd2 @c3 Nxc3 Bxc3 Kxc3 N@b5 Kb4 (Kb2 B@c3 Kb1 Na3#; Kd2 B@c3 Kd1 @e2#) B@c5 Ka4 Nc3#

Q@f5 N@g5 h4!! opening the h-file & mate cannot be stopped

12.3 Interference Mates

Q@c6!! R@b6 B@b7 Ka7 (Ka5 R@a4#) R@a6 Rxa6 Qxa6 Kb8 Qxa8#

The key is to interfere with the Black rook’s defence of b7.

12.4 Block-Escape Mates

Q@a4!! Kxa4 Bc2!! (block-escape!) Kb4 (b3 b5 Kb4 Bd6! blocking escape again! @c5 a5#) Bd6! @c5 (Kxc4 b5#) Nd5! Kxc4 b5 cxb6 Nxb6#

Solution Study

Thanks to NM visualdennis for helping me to collect some of these highlight positions.

You can also review most of the full games played in Season 9.60 here.

Introducing the Candidates

Over the weekend, JannLee & daughter Bella made the draw for pairings in the 2021 Crazyhouse Candidates and together with Zaraza, IgorBu...