The problem called "as-Suli's Diamond" went unsolved for over a thousand years. In shatranj, the "queen" (counsellor) is a very weak piece, able to move only a single square diagonally. It is also possible to win in shatranj by capturing all pieces except the king.as-Suli gave the first move of the solution (1.Kb4) which was the same as Averbakh's solution; Averbakh was impressed with the obvious prowess of the Arab master.as-Suli commented:
“This ancient position is so difficult that there is no one in the world who would be able to solve it, except those I have taught to do so. I doubt whether anyone did this before me. This was said by al-Suli.”David Hooper and Ken Whyld studied this problem in the mid-1980s but were unable to crack it. It was finally solved by Russian Grandmaster Yuri Averbakh.
Solution (from the German Wikipedia) is in the comments. You have 1000 years, starting NOW...
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Solution
Juri Awerbach stated the following main line in the 1980s: 1. Kb4 Kd6 2. Kc4 Ke6 3. Kd4 Kf6 4. Kd5 Kf7 5. Ke5 Kg7 6. Ke6 Kg8 7. Kf6 Kh8 8. Kg6 Kg8 9. Fd2 !! Kf8 If the black Fers tries to escape the corner with 9.… Fb2, it only gets closer to the white king. 10. Fc1 Ke7 11. Kf5, and the king will capture the black Fers and win. Computer help later found a more stubborn defense that Awerbach suspected as-Suli knew too. 6.… Kf8 7. Kd6 Ke8 8. Kc6 Kd8 9. Kb6 Kc8 10. Kc5 Kd7 11. Kb5 Kc7 12. Kc4 Kd6 13. Kb4 Ke5 14. Ka3 Kd5 15. Kb3. The starting position is reached with black to move. It is a forced variation. With the previous extended triangulation manoeuvre, White has given the obligation to move to Black. Black loses after 15.… Kc5 because White now successfully transfers the Fers to c1 and the king to b1. Another possibility is 15.… Ke4 16. Ka2 Kd3 17. Fb4 Kc4 18. Fa3, and White wins, because the black king can no longer attack the white Fers and the black piece falls on a1.
(translation from German Wikipedia by Google and me)
Biolgraphy
From BOARD AND TABLE GAMES FROM MANY CIVILIZATIONS (Vol.1)
by R. C. BELL
BIOGRAPHIES
AS-SULI
Abu-Bakr Muhammad ben Yahya as-Suli was descended from a Turkish prince of Jurjan, whose ancestral home was on the banks of the river Atrek at the south-eastern corner of the Caspian Sea. During the reign of al-Muktafi, Caliph of Baghdad from A.D. 902 to 908, a chess tournament was arranged between the court champion, al-Mawardi, and as-Suli. The Caliph was present and he openly favoured al-Mawardi and encouraged him during the game. At first this embarrassed and confused as-Suli, but he soon re- covered his composure and defeated his opponent so conclusively that there was no doubt who was the better player. The Caliph then transferred his favour from the old champion, al-Mawardi, dismissing him with a bitter pun: ‘Your rose-water [maward] has turned to urine !’
The new champion’s powers of improvising verse, and his attractive personality, maintained him in favour at court for three reigns. After the death of al-Muktafi, his successors, al-Muqtadir, followed by ar-Radi, gave him high positions. Ar-Radi was especially fond of him as as-Suli had been one of his tutors.
A contemporary historian, al-Mas’udi, relates that ar-Radi was once walking in the grounds of his country residence at Thurayya, and remarked on the beauty of the garden with its lawns and flowers: ‘Have you ever seen anything more lovely?’ The sycophants im- mediately began to dilate on the wonders of the garden, praising its beauty and placing it above the wonders of the world. ‘You are wrong, gentlemen, the chess-skill of as-Suli is finer than all of these.’
As-Suli’s reputation remained unchallenged among the Arabs for over six hundred years. His biographer ben Khalliken, who died in 1282, wrote:
‘In chess he stood alone among the men of his generation. None were his equal and his play has passed into a proverb. When men wish to praise a player for his skill they say, “He plays like the Maestro as-Suli”.’
Enough of his work survives in ancient manuscripts for us to assess his status as a master of Shatranj. We can see him criticizing his predecessors in a kindly fashion, though with the condescension of superior knowledge; his favourite openings are preserved, and they are based on definite principles. End games which occurred in actual play have been recorded, and there are comments on his skill in blindfold play; while occasional anecdotes underline his immense prestige.
He was the first player to try to discover the science of the game and to enunciate the underlying principles of play. His book, Kitab Ash-Shatranj (Book of Chess), is laid out in orderly fashion with ten standard openings; common problems in middle play; and a collection of end plays with comments. In the preface to his book he displays interest and skill in solving problems. Finally, he left behind him a pupil of outstanding merit, al-Lajlaj (the stammerer), whose memory is still respected among the Persians, Turks, and the Moghul Hindus.
As-Suli’s other literary works include a history of the viziers; an unfinished history of the ‘Abbasid House; an anthology of poems written by the descendants of Caliph ‘Ali ben abi Talib; a history of Arabian poetry and monographs on several of the more noted poets. Many of these works are preserved in European or Istanbul libraries.
After ar-Radi’s death in A.D. 940, as-Suli fell from favour through his sympathies for the ’Alids, later the Shi’ites, and he was forced to flee from Baghdad and go into hiding at Basra. He died there in poverty in A.D. 946.