visayanbraindoctor: <AnalyzeThis: Did Capa play the Modern Benoni with black? Marshall certainly did.>
Probably not on purpose from the first move. Certainly Capablanca steered this game from round 5 Alekhine vs Capablanca, 1927 into a Modern Benoni by transposition when he had the opportunity. This particular game itself (Capablanca vs Marshall, 1927) occurred in Round 11. Marshall thought to use Capa's own weapon against him. However, it's possible that Marshall already got interested in the Modern Benoni in the New York 1924 tournament when Capa employed it for the first time in chess history with colors reversed in this game Capablanca vs Janowski, 1924. Please see my little research in Benoni (A61).
Because of Capa's role in the Modern Benoni's founding, I believe it should properly be named as the Capablanca Benoni (or the Capablanca System or the Capablanca Opening or the Capablanca Game).
Even after the thrashing Nimzo gave him in a later round (Round 17) in this game Nimzowitsch vs Marshall, 1927 Marshall did not give up.
He once again employed it against Capablanca (of all people!) this time in this game Capablanca vs Marshall, 1928.
Capablanca who had an uncanny sense of danger must have suspected that Marshall had prepared a novelty against the Knight maneuver to c4 (Nf3 - Nd2 - Nc4), which Capa himself employed for the first time in chess history in this particular game itself (Capablanca vs Marshall, 1927) and which Nimzowitsch later also used (Nimzowitsch vs Marshall, 1927 - click on the link above). So he sidestepped any Marshall prep by employing an entirely different strategy. This time he developed his KB to d3, his KN to e2, buttressed his c4 square with b3, opened up the center and the d-file by dxe6, retreated his KB on d3 to c2 thereby allowing the use of the d-file, and then transferred his major pieces to the d-file as rapidly as possible. Marshall got caught off-guard and quickly lost a pawn, and eventually the game. After the thrashing that Nimzo and Capa gave him, Marshall seemed to have given up on the Modern Benoni.
Ironically, it was Capablanca himself who probably ruined his creation's reputation.