Abstract: This talk investigates a non-commutative first-order sequent calculus NCLK. First this talk extends a non-commutative positive fragment to a full first-order sequent calculus LK- having antecedent-grouping and no right exchange rule. This talk shows (1) NCLK is equivalent to LJ, (2) NCLK with the exchange rule is equivalent to LK, (3) LK- is equivalent to LJ, and (4) translations between LK- and NCLK.