Abu Bakr bin Yahya al-Suli

Abu Bakr Muhammad bin Yahya al-Suli (born: 266–267 A.H/ 880 A.D, died: 334–335 A.H/ 946 A.D) (aged 68-69. lunar calendar) was a nadim (boon companion) of successive Abbasid caliphs. He was noted for his poetry and scholarship and wrote a chronicle called Akhbar al-Radi wa'l-Muttaqi, detailing the reigns of the caliphs al-Radi and al-Muttaqi. He was a legendary shatranj (an ancestor of chess) player, still remembered to this day.

Upon the death of al-Radi in 940, al-Suli fell into disfavour with the new ruler due to his sympathies towards Shi'a Islam and as a result had to go into exile at Basra, where he spent the rest of his life in poverty. Born into an illustrious family of Turkish origin, Al-Suli's great-grandfather was the Turkish prince Sul-takin and his uncle was the poet Ibrahim ibn al-'Abbas as-Suli.

Al-Suli's chronicle has long been in the shadow of more famous chronicles such as those of al-Mas'udi and Miskawayh, perhaps because al-Suli was seen as a nadim and not a serious scholar. However, the account is significant for offering an eyewitness account of the transition to Buyid rule. It was during al-Radi's caliphate in 936 that the position of amir al-umara was created, which allowed for the transfer of executive power from the caliph to an amir, a position that the Buyids later used to establish a new dynasty alongside the Abbasids. After this point, the Abbasids never regained their full power. However, al-Suli's account makes it clear that not all power was transferred to the amirs. He treats the period as a time of crisis, but not the end of the Abbasid caliphate.

Al-Suli came to prominence as a shatranj player sometime between 902 and 908 when he beat al-Mawardi, the court shatranj champion of al-Muktafi, and the Caliph of Baghdad. Al-Mawardi was so thoroughly beaten that he fell from favour, and was replaced by al-Suli. After al-Muktafi's death, al-Suli remained in the favour of the succeeding ruler, al-Muqtadir and in turn ar-Radi.

Al-Suli's shatranj-playing ability became legendary and he is still considered one of the best Arab players of all time. His biographer ben Khalliken, who died in 1282, said that even in his lifetime great shatranj players were said to play like al-Suli. Documentary evidence from his lifetime is limited, but the endgames of some of the matches he played are still in existence. His skill in blindfold chess was also mentioned by contemporaries. Al-Suli also taught shatranj. His most well known pupil is al-Lajlaj ("the stammerer").

One of his most prominent achievements is his book, Kitab Ash-Shatranj (Book of Chess), which was the first scientific book ever written on chess strategy. It contained information on common chess openings, standard problems in middle game, and annotated end games. It also contains the first known description of the knight's tour problem. Many later European writers based their work on modern chess on al-Suli's work. He also wrote several historical books.

Al-Suli's Diamond

	a	b	c	d	e	f	g	h
8									8
7									7
6									6
5									5
4									4
3									3
2									2
1									1
	a	b	c	d	e	f	g	h

White to move, White wins

al-Suli created a shatranj problem called "al-Suli's Diamond" that went unsolved for over a thousand years. As this is a shatranj, the "queen" (counsellor) is a very weak piece, able to move only a single square diagonally. It is possible to win in shatranj by capturing all pieces except the king, unless the opponent is able to do the same on the next move.

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.

— 12th-century manuscript from the library of Sultan Abdul Hamid

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. The solution, starting with 1. Kb4, is given in Hans Ree's "The Human Comedy of Chess", and on the web.