Inspired by a paper of Tasaka, we study the relations between totally odd,
motivic depth-graded multiple zeta values. Our main objective is to determine
the rank of the matrix CN,r defined by Brown. We will give new proofs for
(conjecturally optimal) upper bounds on the rank of CN,3 and CN,4,
which were first obtained by Tasaka. Finally, we present a recursive approach
to the general problem, which reduces evaluating the rank of CN,r to an
isomorphism conjecture.Comment: 14 page