International Cricket Council chairman Shashank Manohar has offered his resignation.
The 59-year-old Indian set out his intention to stand down in an email to cricket's governing body, the ICC announced on its official website on Wednesday.
A statement read: "The ICC board will assess the situation and next steps before making a further announcement."
Manohar, the two-time former Board of Control for Cricket in India president, was elected unopposed as the ICC's first independent chairman in May 2016 for a two-year term.
In a transcript of his resignation letter, carried on espncricinfo.com, it is reported Manohar wrote: "I have tried to do my best and have tried to be fair and impartial in deciding matters in the functioning of the board and in matters related to member boards along with the able support of all directors.
"However, for personal reasons it is not possible for me to hold the august office of ICC chairman and hence I am tendering my resignation as chairman with immediate effect.
"I take this opportunity to thank all the directors, the management and staff of ICC for supporting me wholeheartedly. I wish ICC all the very best and hope it achieves greater heights in future."
Reaction to Manohar's decision to quit after just 10 months in the role has been slow to arrive, reflecting the shock that many in the game will be feeling.
But the Board of Control for Cricket in India (BCCI) - an organisation Manohar led between 2008 and 2011 and then again in 2015 to 2016 - has "expressed its surprise at the sudden decision".
In a short statement, the BCCI said: "Mr Manohar's contribution to Indian cricket is invaluable. He is a man of few words but excellent deeds.
"The BCCI committee of administrators was looking forward to a long-term cooperation between the ICC and BCCI with Mr Manohar at the helm of affairs. The BCCI wishes him the very best for his future endeavours."
It is being widely reported in the Indian media that Manohar quit when he discovered the BCCI recently met its counterparts from Bangladesh, Sri Lanka and Zimbabwe to agree a plot to vote against the ICC's plan to reduce the influence of cricket's so-called "big three" - Australia, England and India.
This plan would have ripped up the 2014 agreement that sees about half of the international game's central revenues flow to those three nations. That controversial "big three" takeover was the subject of the award-winning documentary "Death of a Gentleman".
With 10 nations as full members, the ICC needs seven of them to back any reform proposal, a scenario that now looks less likely after India's moves to build a coalition to block the plan and its chief author's departure.
