did tests of course . its not up to yuris usual standerds at all , different lines as opposed to his usual B90s but r4 is a mega draw book and has an answer for most lines,, it came out clear winner, though id not say an easy winner ,but other books here have given r4 harder tests , nice try no cigar ..
but...... VERY shortly we expect mybook22.1 will be screaming for playchess games to open it
Nothing is ever truly lost , just miss placed and awaiting us