Wednesday 30 October 2019

2019 1+0 Candidates Recap & Announcing the Final

The 2019 Bullet Crazyhouse World Championship Candidates are completed after a summer hiatus and the Grand Final between IM opperwezen (Vincent Rothuis from Holland) and JannLee (Justin Tan from Australia) is now underway. The first session of the Final happened last Saturday at 1200UTC with 30 games of 1+0. The second and third sessions will be on the 2nd and 9th November 1200UTC with a further 30 and 40 games respectively to complete the 100 game match. All games will be played on and can be watched on the Lichess TV channels of the respective players as well as being streamed by JannLee (without commentary), Mugwort and okei on Twitch. After the first session opperwezen leads 18-12 with 50.5 being the target for victory. This post is to report how we got here since our announcement of the eight Candidates back in the spring.

The first match of the Candidates was on 21st May between the reigning 2018 World Champion in 3+2 crazyhouse IM opperwezen and the tournament organiser and 2018 CWC Candidate FM littleplotkin (Mark Plotkin from Canada). Opperwezen proved too strong and went on to win six out of his seven matches over the subsequent 31 days, again the first to complete all his matches as in 2018. He only lost to JannLee 14-16. In total he racked up 145 game wins out of 210 games (69% win rate) all but guaranteeing himself a spot in the Final which could only have been denied if two other players scored a greater total of game wins. Despite most matches being completed within 7 weeks as planned, OTB tournaments and the birth of Jann's second child put a stop to the action for a couple of months and the last few matches were not completed till October. With the final match of the Candidates, JannLee overtook opperwezen's game total by one game, scoring 146 game wins, along the way also scoring the biggest demolition of the round robin with 26-4 against VariantsOnly. We are in store for a great Final! Moreover, the winner of the Final will play an exhibition match with a separate prize fund with Jasugi99 (Janak Awatramani from Canada, formerly known as TwelveTeen aka cheesybread on FICS, 12teen on

In third place on 116.5 game wins was chickencrossroad (who famously withdrew from the 2017 Candidates making way for opperwezen to take his place after an intensive qualifying tournament against all-comers). Apart from JannLee and opperwezen, chickencrossroad beat everyone else. In fourth place was penguingim1 on 109 game wins who beat everyone apart from Jann, opper and chicken, and in fifth was mastertan on 96 game wins who beat everyone apart from Jann, opper, chicken and penguin. In 6th was blitzbullet beating littleplotkin in 7th who in turn beat VariantsOnly in 8th, but VariantsOnly saw off blitzbullet in his final game, so the bottom three all won one match. Below is the full table of results and on the second page of the Candidates spreadsheet you can also find all the game links and streams. Thanks to TheFinnisher and LegionDestroyer for helping keep this updated!

See you on coming Saturdays at 1200UTC to watch the Final. To whet your appetite, here are a selection of 40 puzzles of various difficulties which you can either solve in your head, or if you prefer play out against the engine in a Practice with Computer Puzzle Study on lichess. There is also a solutions study. For a video recap of the Candidates (don’t look if you want to enjoy the puzzles below), check out part 1 and part 2 of the Highlights video. Coverage of all the 2019 CWC 1+0 matches (including my own coverage of week 1 of the Finals) may be found in the 2019 CWC 1+0 playlist with 39 videos to date.

Level 1 (1800): Improver

Level 2 (2000): Intermediate

Level 3 (2200): Expert

Level 4 (2400+): Potential Candidate

Instead of solving these in your head, you could also try to play out your solutions against an engine.

Check out the variations here.

We leave you with Jann's own recap of the Candidates and looking forward to the Final:

Keep playing crazyhouse and supporting the community!


Thursday 3 October 2019

Back-Rank Mate

One of the most important mating motifs in crazyhouse (as in chess) is the back-rank mate. Unlike in chess, checks can be blocked in crazyhouse using pieces in hand, so getting the back-rank mate to work is a little more intricate. The final checkmate must either
  • be delivered by a rook or queen adjacent to the king,
  • smother the opponent king e.g. with a pawn on the 7th rank, or
  • exhaust the opponent’s pieces in hand.
These three can be illustrated in the following gif showing three possible continuations in a winning endgame between catask and CrazyAraFish (the actual game followed the second variation).

The best way to learn crazyhouse is through practice. So the following is a study of 31 back-rank puzzles carefully chosen to train different back-rank mating patterns, and getting progressively more difficult so despite being designed with beginners in mind, hopefully even advanced players can enjoy it. Play against the computer and see if you can deliver mate!

Understanding this mating theme will also help when you are on the defending side and need to recognise if you are susceptible to a back-rank mate yourself. If you are ready to see the solutions, they can be found in the following solution study:

If you prefer to sit back and watch someone else solve these puzzles live, then here was the live stream with the-lone-wolf where we explain the puzzles and the-lone-wolf solved them live on stream as well as contributing the final puzzle:


Acknowledgments: Many thanks to lishadowapps for having created the PGN Editor with which the gifs were made in this and my previous blog. Many thanks to the-lone-wolf also for helping to create the instructive video.

Tuesday 6 August 2019

Season 5 of the ZH League

Season 5 of the ZH League was the second Team Crazyhouse League building on the success of Season 4 and inspired by the ZH Summer League of 2017 organised by FischyVishy. While Season 4 was more of a trial with 4 teams of five players, Season 5 had 6 teams of seven players, led by TheFinnisher, xuanet, RapidVariants, VariantsOnly, Gene_Simmons and LegionDestroyer as the board 1 of each team. Team selection was done as in Season 4. Each week, players arranged two games of slow time control crazyhouse against the corresponding board of the opposing team. The time control played on board 1 was 5+5, on board 2 6+6, all the way up to board 7 playing 11+11. We have found this progression of times is favourable because weaker players appreciate the slower time controls (and we even saw some flags on board 7) while stronger players tend to be bored by anything slower. After three weeks of Swiss pairings, we discovered that there were two triangles of teams who needed to play each other, and since it isn’t possible to decompose the six edges of two triangles into two matchings, we needed an extra week so in each of the last three weeks of the season, two teams sat out and took a bye.

Team ZHorro were the champions with a commanding performance winning all of their five matches. Congratulations! Their team was made up of RapidVariants, CrazyHome, grogers, pkr5025, GodBless111, Isachess and darubaru (with Zher0 substituting in as alt for one round). TheIngloriousForkers led by TheFinnisher finished second with 3.5/5, while Cirque du So-Cray came third with 3/5. Top individual performers in the league were TheFinnisher from Finland living up to his number one seeding with 6/10, while CrazyHome from India was top board 2 with 8/10, pepellou the famous lichess streamer from Galicia in Spain was top board 3 with 7/10, pkr5025 was top board 4 with 8/10 and the biggest improver during the course of the league finishing the Season with a zh rating above 2100, charliehorse55 from Canada was top board 5 with 8/10, Isachess was top board 6 with a perfect 10/10, and jwwells42 was top board 7 also with 10/10. Special congratulations to Isachess and jwwells42 for being the players of the league in Season 5. For sure they will both be chosen on higher boards next season!

Huge thanks to colwem especially for keeping the programming of the zh league website working (although this site will go down once it is fully integrated into as well as to the other crazyhouse mods (FischyVishy, kostasvl & Zher0).

In total 184 games were played, and there are too many highlights to be able to share in a blog post (though these will certainly made into puzzle studies). So I will restrict myself here to a single game from Round 1 played on the 25th May, 2019 between RapidVariants and xuanet. I will share six positions from this game and under each image is one of the best variations:

Position 1

White to play!

RapidVariants found the move! 

Position 2

Black to play!

Position 3

Black to play!

Position 4

Black to play!

Also, what should White have played instead of @g3?

Position 5

Black to play!

Position 6

White to play!

In position 6, the immediate N@f7 can in fact be made to work a move quicker, but it is not intuitively easy and also less aesthetically pleasing.

If you would like to practice 80 puzzles based on the games of Season 5, then check out the following links (puzzles 13027-13106), and keep adding one to the puzzle number to see the next puzzle:
There is a progression of difficulties and all puzzles are also tagged by theme. We will write about the definitions of these crazyhouse themes in a future blog, with the purpose being to help new players especially with their pattern recognition.

You can also watch these 80 puzzles live-streamed in a crazyhouse puzzle competition in this 2-part video series (the second video ending with a brief survey of three games from the league).

The big news in the past month is that JannLee’s daughter Bella has a baby brother and the JannLee plan is to form a team for the next generation of Australian bughouse. Congratulations to all the family! In the meantime, Kleerkast has been taking up the reins of elite crazyhouse streaming. So everyone should follow his Twitch to get notified when he streams, and subscribe to his YouTube!


Thursday 23 May 2019

1+0 Crazyhouse World Championship: Candidates & Puzzles

The inaugural 1+0 Crazyhouse World Championship organised by littleplotkin got underway in April 2019. After three knockout rounds (each match best of 20 games), the eight survivors are now playing an all-versus-all round-robin Candidates tournament (each match a full 30 games). The two players with the greatest aggregate game points will face off in a 100-game Final to be scheduled over three or four sessions. 

All updates, scheduling & results are being reported in the 1+0 CWC thread on lichess, but you can also see match times in the Crazyhouse Calendar embedded in the right-hand column of this blog, and many of the matches are being streamed by JannLee, KleerkastFumitoks and others, and you can catch up on the recordings on their respective Twitch channels or on the 2019 1+0 CWC playlist on YouTube. 

Most of the early matches were quite one-sided as the stronger seeds easily prevailed. A big round one upset was KyleLegion succumbing to SwiftDevil 13-7 after losing the first ten games before getting his crazyhouse shoes back on and taking 7 of the next 10. I hit a new peak rating above 2250 in losing my own match to LeProfessionnel 13.5-6.5. Round 2 saw a few more closer matches with Fumitoks beating emrty 12.5-7.5 after emrty came back from 0-9 down, penguingim1 beating TCubesAK 13-7, retardedplatypus123 beating chewythechewer 12-8, Kingswitcher getting past B0N0B0 on tiebreaks winning the last four games to win 12-10 and closest of all garnek123 beating mathace 11-9. In round 3, the three most exciting matches were mastertan with some powerful play to see off a challenge from retardedplatypus123 12-10 on tiebreaks, VariantsOnly edging ahead of xuanet 11-9 to create the upset of the round and littleplotkin surviving through the time scrambles to beat garnek123 11-9. The two dominant performances were from JannLee beating pknm 18-2 and opperwezen beating JohnStuckey by the same score. Meanwhile, penguingim beat Kingswitcher 11-8 over two sessions, blitzbullet pulled ahead of Kleerkast 11-6 with aggression and speed winning the day, and chickencrossroad sent a warning to the big two with a 15-5 demolition of Fumitoks who just the previous week had berserk-beaten JannLee in a 3+2 Elite Arena.

So the eight Candidates who will do battle for the 1+0 CWC crown are JannLee, opperwezen, chickencrossroad, littleplotkin, blitzbullet, mastertan, the grandmaster penguingim1 and the hopefully soon-to-be-grandmaster VariantsOnly. The match times will be posted up on the 1+0 CWC thread, updated in the Calendar and you can watch the games live either on the lichess tv of the respective players, or on the live streams from JannLee and others. Results will be updated in the Candidates cross-table. Jann is also crowd-funding prize money for the eight Candidates to supplement the $500 prize for the two Finalists (split 3-2), half of which was set aside by littleplotkin and matched by the Crazyhouse Fund managed by JannLee from prize money returned by 2018 winners and donations for the benefit of future events.

Below are sixty puzzles taken from positions played so far in the competition. They are grouped loosely by theme. Check out the associated solution study to see the matches they came from, the full variations and the themes they represent. Or you may prefer to watch them solved live on my stream in this instructive video on Basic Crazyhouse Ideas: Puzzles from the 2019 1+0 CWC (video embedded at the end of this blog).

Back Rank

Smothered Mate

Picking Up the Queen with Check

Mating Patterns with the Queen

Queen & Knight Calculation

Mating Patterns with Rooks or Knights

Diagonal Mates & Double-Take Mates

Mating Patterns with Minors

Exploiting Pins & Potential Forks

Deflect the Defender

Deflect the Defender 2

Clearance Mates

Magnet Mates

Combining Defence & Attack

Correct Defence

I hope you enjoyed these puzzles. Here again is the solution study with the games these positions came from, the themes they represent and the full variations so you can check your solutions. And here is the instructive video where I solved all these puzzles live on stream:

Do join us to watch the live action in the Candidates 
& come to the House Variants Discord to chat with other players and spectators.

 See the calendar for upcoming matches, and
check out the results in the Candidates cross-table.

May crazyhouse flourish!


Thursday 25 April 2019

Season 4 of the ZH-ero League was Team Crazyhouse!

The crazyhouse spin-off of the Lichess4545 league completed its 4th season a couple of weeks ago and we have 48 players already signed up for the 5th season which is will start soon. Like Lichess4545 on whose Slack the league operates, the ZH-ero league encourages the play of online chess at a slower time control. So while the zh standard is 3+2, with elite players often relishing 1+0, the league games are 5+5 or slower. The first three seasons were all individual leagues, but Season 4 trialled a new format with a team league (4 teams of 5 players) played over three weeks with players facing off against their opponent on the corresponding board each week. Each match comprised two games of (4+b) + (4+b) crazyhouse on board b, which meant board 1s played 5+5 while board 5s played 9+9. 

Four top players of the game were recruited in to be the board 1s of each team in JKtheBullfrog, TheFinnisher, Mugwort & RapidVariants, and among other invites were the Dutch International Master VariantsOnly who proved to be a strong board 2, and the popular streamer pepellou from Spain, a recent crazyhouse enthusiast who would go on to stream all his matches on board 3. Team selection was done by board 1 players choosing their board 2s in reverse order of strength, then board 2s selecting their board 3s in the reverse order in which they were selected and so on. As well as the league founder, Zher0, kostasvl, colwem, FischyVishy & I (okei) were introduced as crazyhouse mods to help run the league. We are particularly grateful to colwem who has spent hours programming the crazyhouse team league website to do clever things like recognise when participants schedule or start a game and automatically post up the schedule, the game link and the result on the website. It is not yet perfect, but we are confident enough to roll out Season 5 to as many people as want to join.

Now, for the rest of the blog, we will recap what happened in Season 4 and share a plethora of puzzles for your enjoyment. Here were the rosters of the 4 teams, with PawnInTraining and fgalla also subbing in as alts on boards 2 and 3 respectively:

In the end, FinnishThem, led by TheFinnisher came home victorious, but only on tiebreaks thanks to game points won. So every game mattered! TheFinnisher was equal top-scoring board 1 with 4/6, okei scored 2/6 on board 2, ErinYu and colwem both scored 3/6, and asian42, learning crazyhouse for the first time, was top scoring board 5 on 4/6. Congratulations to everyone for such a well-fought season.

Special congratulations to IM VariantsOnly for being the man of the season with a perfect score, winning 6/6 on board 2 with a performance rating of 2994 — echoes of IM lovlas who in Lichess4545 once scored 8/8.

He will be joining TheFinnisher, RapidVariants, Gene_Simmons and the attacking legend xuanet among others as board 1s in Season 5.

As a curious statistic, Black won 58% of the games on board 1 and the White advantage in crazyhouse (+1.9 according to Stockfish) which forces us to play 2-game matches was in fact most pronounced on board 5.

For a recap of the games and positions in Season 4, check out the end of season recap stream, embedded at the end of the blog. You may also be interested to check out the playlist of previous recap videos as well as live streams of zh league matches. In the video, I discuss a couple of the games and I spoil most of the puzzles below. To practice them yourself against the computer, click here, or to see the solutions with full variations click here. At the end of the blog you can find hints to these puzzles and the video recap.

Level 1 (1600 zh)

Level 2 (1800 zh)

Level 3 (2000 zh)

Level 4 (2200 zh)

Level 5 (2400 zh)

Level 6 (2600 zh)

Non-Mating Puzzles 1 (2000 zh)

Non-Mating Puzzles 2 (2600 zh)


Level 1: The king is in a mating net. Seal the mate!
Level 2: Tighten the mating net!
Level 3: Create the mating net! If necessary, draw the king to the mating square.
Level 4: Deflect defenders & calculate.
Level 5: Calculate deeper.
Level 6: Sacrifices, intermezzo moves & discovery ideas.

Non-Mating Puzzles 1: be aware of forks!
Non-Mating Puzzles 2: the bishop is the most dangerous attacker!


You can practice these puzzles yourself against the computer here or see the solutions with full variations here.

Keep playing crazyhouse!


Wednesday 17 April 2019

Introducing the 1+0 Crazyhouse World Championship

The 1+0 Crazyhouse World Championship is underway organised by littleplotkin! There were 67 entrants who made the registration deadline of April 13th. Three had to be excluded for having played insufficient games of crazyhouse, leaving 64 participants in a single elimination knockout. Once the field is reduced to 8, there will be a round robin Candidates phase, the top two then facing off to become the 1+0 Crazyhouse World Champion. 

At the elimination stage, participants have a week to get in touch with their assigned opponents and play the best of 20 games, so the first to 10.5 wins. If the match isn't played and no contact is made by either player with the organiser littleplotkin explaining why, then it will result in a double forfeit. In case of a tie, the match continues a further couple of games and again until the tie is broken. 

Scheduling and results should be posted in the Championship thread on lichess. The Candidates phase will be 30 games exactly with every game counting towards the tally of each player. Therefore, number of matches won and head-to-head only count as tiebreakers. The Final will be 100 games scheduled over three or four different dates.

There will be prizes for Candidates, Finalists and for the Champion. The exact prize structure is yet to be determined but thanks to JannLee, opperwezen and to other members of the crazyhouse community who have already stepped in to offer money towards the prize fund.

The first round has a deadline of 28th April. Participants should message their opponents as soon as possible and contact littleplotkin in case of any difficulties in scheduling. Each match of best to 20 is likely to last at most 40 minutes. Here is the full draw: 

Thanks to CrazyHome, somethingpretentious and theLAZYmd for helping draw up the list of entrants and order them by average of current and peak crazyhouse rating with some nifty coding to create the seeding.

Have a great tournament!


P.S. For those looking forward to the official 3+2 Crazyhouse World Championship, this is forecast to start at the end of May.

Friday 1 March 2019

Season 3 of the ZH-ero 10+10 Lichess League

Season 3 of the ZH-ero league (organised by Zher0 as an offshoot of the Lichess4545 classical league) concluded in February 2019. For the third season in a row, okei (that's me!) finished in first place, and clear first as in season 2, but for the first time with 7/7. In Season 1, I had scored 6/7 tying for first with FischyVishy, despite losing 2-0 in our head-to-head, while in Season 2, I had scored 1-1 draws against both Antic and yago666 to finish a half-point ahead of the former on 6/7. Again in Season 3, yago666 proved to be stiff competition, a mate in 3 away from tying our head-to-head (see game below), but he missed a couple of chances and then missed the final two rounds of the season, so it was FiveKnights on 5/7 who was the runner-up and colwem on 4/7 who came in third.

In March 2019, the crazyhouse league will be entering a new era, trialing a team format and with a special website on which it will be organised created by colwem. Again, all communications will take place over the Lichess4545 Slack and players must abide by the Slack’s rules. In particular, players under the age of 16 are unfortunately not entitled to participate, and all player alts will be vetted by Lichess mods to make sure they have an impeccable record of fair play. We will also have some big names signing up including JKtheBullfrog, TheFinnisher and VariantsOnly. The time control will also be changing to meet the preferences of the participants, so players on board 1 will likely play 5+5 while players on lower boards may still play 10+10 as in previous seasons.

As a review of season 3, here is the decisive game between myself and yago666 with detailed annotation, followed by a series of 15 crazyhouse puzzles taken from this season’s games. 

This series of puzzles is aimed more at the beginning crazyhouse player, unlike some of the tougher puzzles we have shared previously on this website. However, we still hope it will prove enough of a challenge that even an elite player might struggle to get a perfect score. It is followed by hints, first moves, and links to a study where full variations may be found.

Basic Crazyhouse Puzzles

Puzzle 1: White to play (kostasvl - Forhavu)

Puzzle 2: Black to play (UpGoerFive - colwem)

Puzzle 3: White to play (yago666 - kostasvl)

Puzzle 4: White to play (halloway - HighonPotnUse)

Puzzle 5: Black to play (Forhavu - colwem)

Puzzle 6: Black to play (GardenPlant - FiveKnights)

Puzzle 7: White to play (kostasvl - UpGoerFive)

Puzzle 8: White to play (halloway - okei)

Puzzle 9: White to play (colwem - yago666)

Puzzle 10: White to play (Zher0 - yago666)

Puzzle 11: Black to play (okei - Zher0)

Puzzle 12: White to play (kostasvl - colwem)

Puzzle 13: White to play (okei - halloway)

Puzzle 14: White to play (colwem - kostasvl)

Puzzle 15: Black to play (gokuba - GardenPlant)


1. Magnet Mate (disturb the king to a checking square)
2. Smothered mate
3. Take pieces with check
4. Queen & Knight mate
5. Block the King’s escape route
6. Queen Invasion
7. Activate pieces followed by Diagonal Mate
8. Create Weaknesses
9. Is there any threat to White’s king via d2?
10. Defend with tempo
11.  Counter-Attack
12. Deflect Defender
13. Keep Initiative
14. Attack on a Colour Complex
15. Treble Knight Smother

First Moves

1. R@h8 followed by R@h7 or N@f7 followed by second rook@h8.
2. N@h3 followed by Q@g1 and Nf2 smothered mate, found by colwem.
3. Bxf7 (taking the rook later whenever the king takes on g5) and N@h8 (distract the defender of f7) both mate. The former mate was executed by yago666.
4. N@b8+
5. B@g3+!!
6. Qh4 (Ke2 R@g2 followed by Qf2) Kg2 Qg3 Kf1 Qg1 Ke2 R@f2
7. Qe4+!
8. e6!
9. RxR. d2 is exposed, but there is no imminent threat.
10. B@a4+ defending c2 with tempo. If @d7, exNf6 exf6 Bxd7 Qxd7 QxRa8+ B@d8 R@e2+! again defending c2 with tempo.
11. There are many decent moves attacking directly the White King: N@h4, N@g5, B@h5, B@g4, R@g6,  each with an imminent threat. For example, N@h4 BxQf7 B@f3 wins back the White Queen with an unclear position because if gxf3 N@h3 followed by R@g1 leads to a smothered mate. However, any Queen move for Black is bad because it loses initiative. Even QxBe5 allows dxe5 and White has initiative.
12. N@f3 (threatening Q@h2 mate) gxf3 Q@h3 mate. The g2 pawn is overloaded.
13. Qxd5! Unlike in puzzle 11, there is not enough material in hand to counter-attack and the pawn on e5 will be recaptured.
14. B@f6 and B@h6 are both strong. Black’s knight has guard duty on g7, so B@f6 hitting the queen is probably a smidgeon better.
15. N@f3 and N@h3 both mate in 6. If N@f3 Kh1, there is the beautiful treble knight mate with N@g3 fxg3 (hxg3 R@h2 is mate) R@g1 Rxg1 N@f2 mate with the third knight. So N@f3 forces gxf3 and the king is exposed. There follows: N@h3 Kh1 @g2 Kxg2 Nf4 Kg3 (Kg1 or Kh1 are no safer) Qxg5 @g4 @h4 mate, found by gokuba.

Here is a lichess study of highlights of the 3rd crazyhouse ZH-ero league, including all the above puzzles, mostly with full variations, some to practice with the computer. If you prefer to look at these highlights in video form, here is the video recap of season 3:

We look forward to great things in season 4. You can register here by inserting your lichess username and then clicking on the link again.


2021 Crazyhouse World Championships Final

The 2021 Crazyhouse World Championship (CWC) reached its apex with the Grand Final between Champion  Jasugi99 , NM Janak Awatramani from Can...