LMI Monthly Test Authors

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Photo of Riad Khanmagomedov

Riad Khanmagomedov

I am, 43 years old, chief editor of the most popular in Russia crossword magazine "777". I have participated in and won multiple Puzzle, Sudoku and Crossword competitions in Russia, Ukraine and Belarus, and have participated in 10 WPCs and 4 WSCs. I have authored puzzles for the 24 HPC, Moscow Puzzle Cup, Turkish Puzzle Championship, Zagreb Open, UKPC. I have also invented several puzzle types (Build a maze, Cube with Snakes, Graffiti, Palindrome Sudoku, Paper ships, Penta-gluing, Pentaroll / Pentoroll, Skyscrapers Sudoku, Sudoku builder, Trid, Watches are notable ones among them). I also authored the book Minesweeper Collection. I am especially fond of Palindromes and have created many Palindrome-related puzzles, which you can see at Palindromowords.

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Ivan Koswara

Ivan Koswara, better known online as chaotic_iak, is a puzzler from Indonesia. Although he has shown a liking to logic puzzles since early 2000s, he has only began participating logic puzzle competitions seriously since 2012. Due to the lack of any puzzle foundations in Indonesia (or his ignorance to any of them), he has never gone to any on-site puzzle competitions, although he is a pretty regular participant in Logic Masters India's puzzle tests and he occasionally participates in other puzzle competitions. He has made several puzzles on his blog. His favorite puzzle genre is Fillomino. Outside of the puzzling activities, he enjoys doing math, computer science, and gaming.

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Swaroop Guggilam

My journey to puzzles began by accidental participation in puzzle event at IIT Bombay in 2009, where I finished at 4th place. My eagerness to know more about puzzles increased, and I gained more information about the World of Puzzles from Prasanna Seshadri and Rohan Rao, whom I met during that event. Henceforth, I frequently started participating in LMI contests. In 2010, I started creating my own puzzles and published on my blog http://swaroopg92.blogspot.com/ . After missing a place in Indian Puzzle Team for 4 consecutive years by marginally, I finally broke my jinx in 2014 and made it to team. WPC 2014 was my 1st championship experience as an Official Member of A team. I made it to Top 50 at World Puzzle Championship 2014, London and hope to keep on improving in future as a Solver as well as Creator. Now I contribute puzzles for Penny Dell Magazine in US, Patron rewards for LMI and few other National/International competitions. I would like to finish saying that, ‘Surely world of puzzles is a fantastic place to be in’.

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David McNeill

David McNeill has been a puzzle enthusiast since childhood. He first represented the United Kingdom at the World Puzzle Championship in 2003 and his first appearance at the World Sudoku Championship was in 2007 when he somehow managed to finish in 4th place. David’s puzzle-setting debut was in 2014 when he contributed puzzles for the 24 hour puzzle championship and the 2014 World Puzzle Championship in Croydon.

David is a lecturer in Electrical and Electronic Engineering at Queen’s University Belfast. His wife and 3 daughters barely tolerate his puzzle interests, which also include cryptic crosswords. They are slightly more tolerant of his interest in botany. He is a member of the Botanical Society of Britain and Ireland and co-ordinates botanical fieldwork in County Antrim.

Photo of Richard Stolk

Richard Stolk

My interest in solving logic puzzles dates back to 2003. Soon I discovered that creating puzzles is as much fun as solving them. I am boardmember of the official Dutch puzzle association (World Class Puzzles from The Netherlands). We have our own website www.wcpn.nl where a fresh puzzle can be solved daily. You can find a lot of my puzzles there. Next to that you can try my weekly Friday-noon-puzzle at Logic Masters Germany. On december 1st, 2013 I started my "Sudoku Variants Series" a unique project in which I publish a different sudoku variant every week. Since 2007 I contribute puzzles for the Dutch and German sudoku Championships and also for WPC/WSC in London in 2014. Creating and solving puzzles can be combined easily with my other great hobby: I really enjoy listening to progressive rock music (Dream Theater, Riverside, Haken).

Photo of Rohan Rao

Rohan Rao

I started solving puzzles in 2007. With interest and passion, practise and curiosity, I entered the world of puzzles by participating in various online competitions and national championships. I started my blog 'The Logical World Of Puzzles' in 2008. I won the Indian Sudoku Championship in 2010 and the Indian Puzzle Championship in 2010. I have represented India in WPC 2008, 2010 and WSC 2009, 2010. I enjoy creating puzzles and hope to organise a WPC/WSC in India some day.

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Rakesh Rai

I am into puzzles and sudoku since 2007. I am an average puzzle solver and love solving tough puzzles.

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Rishi Puri (purifire)

Rishi is the Indian Sudoku Champion, 2014, stood 9th in the WPF Sudoku Grand Prix 2014, Winner of the Times National Sudoku Championship India in 2013, the Times National Sudoku Championship UK in 2012 and twice Runner up at the Thailand International Sudoku Championships in 2011 and 2012. He is actively involved in a lot of online sudoku competitions and regularly publishes new Sudokus and discusses solving techniques at his blog Sudoku Mania.

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Nikola Zivanovic

Nikola Zivanovic is Serbian puzzler, triple sudoku and puzzle champion of his country. Three times he was finalist of World Sudoku Championship. He is a member of the bronze Serbian sudoku team from Zilina, Slovakia (2009). Nikola is also known as a composer of various logical and enigmatic riddles.

Photo of Prasanna Seshadri

Prasanna Seshadri

I was introduced to puzzles by Rohan Rao in 2010, and I participated in IPC 2010 a few months after I did my first LMI test and finished at 6th place. This encouraged me to be more competitive along with enjoying the puzzles and sudokus and in 2011 I made the Indian Sudoku team that went to the World Championships in Eger. I then started creating puzzles at the start of 2012 and started a blog where I upload puzzles frequently. My first exposure into creating puzzles for competition scenario was my single puzzle in the Puzzle Marathon. About a month after this I was employed by a local news daily called life-365 and have been contributing a daily puzzle there ever since. My competitive abilities have also improved culminating in a 2nd place finish at IPC 2012, and I hope to keep improving, both at solving and creating puzzles.

Gabriele Simionato

I didn't know about puzzle games before attending the 1st World Sudoku Championship in 2006. I started solving Sudokus in preparation for the competition, and participated in the Italian championship that year, earning a 3rd place finish. Since then, my life changed a lot: now I own my puzzle company and I enjoy sharing my games to other puzzles enthusiasts. My favorite sudoku variation is Diagonal Sudoku, but I am best known for the introduction of Sudoku & Dragons. About puzzles, I enjoy solving everything that involves loops, especially Yajilin. Also games like Corral and Parking meet my taste. I have developed interest in Maths, and other "nerdy" things, like Rubik's Cube: my personal best is 39''.

Matus Demiger

See below.

Yosuke Imai


Atsumi Hirose


Takeya Saikachi


Daisuke Takei


Photo of Matej Uher

Matej Uher

I have started solving logic puzzles since 2008, but first time I took part on WPC Eger in 2011. My most favorite puzzles are loop puzzles, tapa and fillomino. In 2012 I got bronze medal at Slovak Puzzle Championship and joined the Slovak squad to WPC in Croatia. I'm also interested in doing sports, climbing and sleeping. I really hate vegetable and sad mood.

Ko Okamoto (xevs)

27 years old worker for a financial company. Several times participated WPC and 4th was the highest rank (2008, 2011). twitter: @xevs99

Photo of Denis Auroux

Denis Auroux

I'm a 36 year old French mathematician working at UC Berkeley (after spending earlier parts of my career in Paris and at MIT). I first got introduced to WPC-style puzzles in 2000, as a member of France's first team to participate in that event. 10 WPC participations later, I'm still just as much into puzzles (albeit not as fast as I used to be), and have gained experience as a puzzle designer by authoring part or all of several French WPC qualifying tests.

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Gyula Slenker

He's programmer and puzzlemaker. He's proud father of more children :) He made puzzles for hungarian magazines for 10 years. He made puzzles for WPC in 2005, one of his puzzles was sunspots. (See IPC 2011)

Photo of Pál Madarassy

Pál Madarassy

The world champion in 2007 (Rio de Janeiro), and he participated all WPC's from 2002 except 2005, when he made puzzles for hungarian WPC. He has a 2 years old daughter.

Photo of Zoltán Horváth

Zoltán Horváth

I solve puzzles from 1999 when the first hungarian logic magazine was issued. I went to my first competition in 2001, and I could started in the WPC as the member of B team. I was one of the last puzzlers on this competiton, but I got a lot of experiences. I participated all WPCs from 2003 (except 2005) and all WSCs. My best result is 4th in WPC (Opatija, 2004), and 5th in WSC (Lucca, 2006). Some example from my puzzles in 2005: Dutch snake, tent sectors, Tiger in the woods.

Andrey Bogdanov

Few times Russian puzzle champion, participated at World Puzzle Championships. Supports internet site of Russian puzzle club (Diogen). At 2008 was a principal author for puzzles of WPC in Minsk, also has authored two books of puzzles.

Seungjae Kwak (Kwaka)

I started solving puzzles in 2001. That was the first year (and so far, the only year) I participated in the WPC. I started solving Sudokus in 2007. I won the 1st Korea Sudoku Championship but unfortunately, I couldn't participate in the 2nd WSC because I was in the army (another player participated in my place). To make up for this I try to participate in all the on-line competitions including LMI monthly tests. These days I enjoy making sudokus rather than solving puzzles. I want to be not only a good player but also a good author.

Hwangrae Lee (Spica)

I'm a 26 year old graduate student, majoring in mathematics. I started to solve Sudoku from 2010, and now I'm interested in both solving and making variants. My birthday is September 21st, so my sign is Virgo. That's why I'm using my nickname "Spica", which is the alpha star of Virgo.

Grant Fikes (mathgrant)

Grant Fikes is a logic puzzle author in Abilene, Texas whose puzzles have appeared in Sudoku Xtra and in Akil Oyunlari, as well as on his own blog where he has posted hundreds of puzzles. His online persona is an anthropomorphic fox/badger hybrid.

Photo of Palmer Mebane

Palmer Mebane (mellowmelon)

Palmer Mebane's first major competition was the 2010 WPC, which he participated in as a member of the US team that won the competition. On the constructing side, he has posted hundreds of puzzles at his blog Melon's Puzzles.

Photo of Stefan Heine

Stefan Heine

I am a German puzzle-maker from Hamburg. Since 1995 making puzzles is my main job and I work for about 400 publications around the world - most of them in German speaking countries. I have been to all WSCs since 2006. I developed all sudokus of the US Sudoku Championships in 2009. For the WSC 2010 in Philadelphia, I made some puzzles for the contest and since Hungary 2011, I am the captain of the German sudoku team. In 2005, I organized the national German sudoku championship and have been creating the puzzles for it since then.

Photo of Serkan Yurekli

Serkan Yurekli

I have been making puzzles for 5 years and I started to focus on solving in the last 2 years. I am the editor of Akil Oyunlari puzzle magazine and we have published several books including logic puzzles. Inventing Tapa puzzle type and organizing OAPC series are the most valuable works I have done among these.

Photo of Sylvain Caudmont

Sylvain Caudmont

40 years old french player, I discovered sudoku variants in 2009, around 3 years ago. I was team member of France at WSC Eger in 2011. I also coauthored one sudoku book in 2011 and from time to time I create some sudokus for tests or specialized publications.

Zuzana Hromcová & Matúš Demiger

Zuzana, 16 years old high school student, participated twice at WSC and once at WPC. Few days ago got bronze medal at Slovak Sudoku Championship and joined the Slovak squad to Eger 2011. She likes visual arts, pizza and collecting signatures, contrary sports and skyscrapers puzzles belong to her non-favorite.

Matúš, 18 years old student of journalism, took part at one WSC and three WPC and he also reached the Slovak nomination to Eger, in both championships. His passions are football, menthol sweets and his pencils, however he dislikes classic sudoku and ice-hockey.

Together, they were co-authors of the 5th Sudokucup and many regular Slovak contests. Matúš also constructed sudoku for the 4th WSC in Žilina, puzzles for the 11th 24 HPC and he is the editor of Slovak crossword magazine Lišiak.

Photo of Frédéric Stalder

Frédéric Stalder (Fred76)

35 years old, I'm a Swiss trumpet player who got lost in the world of sudoku. I discovered variants in 2009 and it became an obsession for me, so when I don't have my trumpet in my hands, I like playing and creating sudoku ! You can find some of my creations on my blog: Variantes de Sudoku

Photo of Tawan Sunathvanichkul

Tawan Sunathvanichkul

Tawan Sunathvanichkul is a 19-year old college student from Thailand. He discovered puzzles when he was around seven and started making hand-drawn puzzles since then.
He is the 2011 national crossword puzzle champion and won several sudoku titles in his country. Most of his puzzles were constructed during boring lectures – with him occasionally getting caught.

Photo of Thomas Snyder

Thomas Snyder (motris)

Thomas Snyder is a 2-time World Sudoku Champion and 5-time US Puzzle Champion. He has authored 4 books of puzzles, including the recently released TomTom Puzzles.

Bastien Vial-Jaime (Ours brun)

Obsessed by logic since my very young age, I got caught immediately when I discovered sudoku, from which I entered the world of logic puzzles. Since then, I have been trying to share my time between puzzle solving and organizational activities such as contributing to online and paper competitions, as well as specialized publications. I am also webmaster of ffsudoku.com and I recently co-authored a sudoku book.

Zoltán Gyimesi

I am 34, married and have 3 children. I love to solve logic puzzles and sudoku, but I had to skip a lot of world championships due to my main profession, which is to play chess. I am a professional grandmaster since I am 19, my biggest successes are to be Hungarian champion, Rapid European Champion, and winning silver medal with the Hungarian Team on the Chess Olympiad. I am sure to be the best puzzler among chessplayers, and the best chessplayer among puzzlers :-) I construct puzzles very rarely, they are usually chess related. But those for LMI are exceptions!

László Osvalt

I am László Osvalt, age 40. I am dealing with logic puzzles for 13 years. I was team member of Hungary on several WPC and WSC races since 1999. My favourites are Kakuro and Snake-like puzzles, and the 24 Hours Puzzle Championships. Crossword puzzles are the other large area of my interest.

Károly Kresz

He participated on more WPC in 1990s, his best position was 8th in Brasov (1995) and 11th in Stamford (2000).
He made puzzles for WPC in 1999. And he was the author of the first hungarian logic magazine for many years. He was more times 3rd with team.

Zoltán Németh

He participated on WPC 5 times (2001, 2002, 2004, 2007, 2010) HIs best result is 22th, and 3rd in team (Opatija, 2004). He was the puzzle director in 2005, and in this year (2011) again.

Photo of Tom Collyer

Tom Collyer (detuned)

Tom Collyer runs the blog detuned radio, and publishes an original Nikoli-style puzzle every Friday. Away from creating puzzles, he is twice winner of the UK sudoku title, and has participated in three World Sudoku Championships.

Jakub Hrazdira (Gotroch)

Murat Can Tonta

19 years old, Murat is a puzzle designer and enthusiast from Turkey, with a particular liking for loop-based puzzles. His puzzles are regularly published in Turkish logic puzzles magazine Akil Oyunlari and he authored a 24HPC set alongside Serkan Yürekli. He is also an author and judge at the website PuzzlePicnic.

Photo of Geoffroy Hermelin

Geoffroy Hermelin

41 years old, passionate of computer, music, sudoku and other, always ready to participate in the craziest projects.

Laurent Pierre

37 years old, laboratory technician in perfumery, passionate of riddles of all kinds, of trekking and discoveries. Sudoku lover and novice in the creation of puzzles...

Photo of Bram De Laat

Bram De Laat (para)

I started logic puzzles about 10 years ago after running in an edition of Breinbrekers advertising the Dutch puzzle championship in a bookstore. I instantly noticed I had a knack for these kind of puzzles. I've won one Dutch Puzzle Championship and one Dutch Sudoku championship since then and participated in 5 world championships. Since 4 years I've also been designing puzzles, which can be mostly found on Puzzlepicnic.com and in Breinbrekers.

Photo of David Millar

David Millar

David Millar is a puzzle author as well as a graphic and web designer, and posts new puzzles at least twice weekly on The Griddle.

Photo of Zafer Hüseyin Ergan

Zafer Hüseyin Ergan

Zafer Hüseyin Ergan is a puzzle enthusiast from Turkiye. He had become a puzzle fan for about ten years. His favourite puzzle types are optimization puzzles and sudokus.

Photo of Chen Cen

Chen Cen (cpickerel)

I started to play sudoku 4 years ago and quickly became a dead sudoku fan. I was the twice Chinese Sudoku champion and 7th position of the 5th World Sudoku Championship.

Photo of Jin Ce

Jin Ce (jcvb)

I'm 13 years old. I like playing Sudoku, designing puzzles and programming.

Photo of Jan Mrozowski

Jan Mrozowski (janoslaw)

Jan Mrozowski is current and double World Sudoku Champion.

Photo of Tejal Phatak

Tejal Phatak

I started solving puzzles in 2007 after the National Sudoku Championship, in which I participated for 'fun'. Having missed to qualify in the Indian team by just a position or two in 2008 and 2009, I finally made it to the team for WPC 2010.

Photo of Amit Sowani

Amit Sowani

I had been introduced to WPC style puzzles and sudoku in 2005, through the national puzzle championships then organized by Hendrik. After participating in a couple of WPCs and one WSC I moved towards the organizing aspect of these competitions since WSC 2008 which we organized in Goa. I hope to see the Indian team do well and stand among the top teams at the world championships. Hoping to return to participating too :)

Mock Test Authors

Several authors contributed to LMI Mock tests.

  • Rajesh Kumar
  • Jakub Ondrousek (jaku111)
  • Branko Ceranic (skywalker)
  • Maruska Benediktova (cauchy)
  • Kshitij Sharma
  • Gaurav Korde
  • Hitesh Gupta
  • Ritesh Gupta

The authors are sorted by order of their tests appeared at LMI (newest test author at the top)