The correspondence player (and now CC Senior International Master) Jonathan Tait discovered this around 1986 or 1987, and racked up a overwhelmingly positive score before publishing an article in Correspondence Chess in 1995. It’s rare that analysis from twenty years ago holds up so well: most of the essential points are present.
Later a major improvement was found for Black in Harding-Arounopoulos, World corr Ch 22, ½-final-05, 1997-99, and this classic game formed the foundation of the entire theory until as recently as 2010: see the discussion in Moskalenko’s The Wonderful Winawer (New in Chess 2010).
But theory turned again with a counter-improvement for White, after which the main line reaches the diagrammed position, with Black to play. The initial analysis given by Watson (ChessPublishing.com, May 2011) indicated that Black was lost. Strangely, though, several correspondence players have contested this verdict, and there are now nine practical examples in all. So far, though, Black has yet to record even a single draw.
Black needs new ideas. (For which see issue 24 …).