The Marshall Defence to the Queens Gambit Declined which he tried against Alekhine. I think it is inconsistent with 1.....d5 in that Black has to give up the centre pawn he has just put there.
Exchanging a centre pawn for a side pawn and removing Black's foothold in the centre.
Black brings out his Queen early. The danger with this is that White can catch up with development by bullying the Queen which will have to waste time running.
4. Nb1c3 Qd5f5
An interesting choice. White has to think about the threat of Ne4 in conjunction with Bb4 hitting f2 and c3.
5. Ng1f3 e6 6. e3 a6
A wasted move I feel. If white plays Bb5+ then Bd7 offers the exchange of the bad bishop when Bxd7 Nbxd7 is a step backwards for white.
With this attack on the Queen white has caught up with development and can claim a mini advantage of the extra centre pawn.
7... Qf5h5 8. O-O Bf8d6
Dreaming of getting something going against h7 I imagine, but inviting white's next ...
... threatening the pawn fork e5.
Black wants to look busy and so moves the bishop away from the fork.
But the negative side is that it is out on a limb and further precautions are necessary to make sure it is defended when Black has responded to the check. The old chess books I read when I was learning the game always mentioned the importance of gaining the initiative.