He learned to play chess before the age of five, developing a promising talent that led to junior honours, including the London under-14 and British under-16 titles.

By 1973, he was able to top a tournament in Canterbury (ahead of Adorjan) and speculation began to grow that England had another potential runner in the race to become the country's first grandmaster.

1973 was also the year when Stean entered the (Teesside) World Junior Chess Championship and finished third behind Miles and tournament victor Alexander Beliavsky (ahead of Larry Christiansen).

During this period, Stean frequently had to put aside his own playing ambitions, as he was engaged as one of Viktor Korchnoi's team of seconds for world championship campaigns in 1977–78 and 1980–81.

In many respects, the partnerships that developed were reasonably successful; Korchnoi brushed aside some powerful rival Candidates like Boris Spassky, Robert Hübner and Lev Polugaevsky en route to his two finals with Karpov.