Abstract. The paper introduces NJg , a variant of Gentzen's NJ natural deduction system, in which the implication elimination rule has no minor premise. The NJ g -systems extends traditional ND-systems with a new kind of action in derivations, assumption incorporation, a kind of dual to the assumption discharge action. As a result, the implication (I/E)-rules are invertible and, almost by definition, harmonious and stable, a major condition imposed by proof-theoretic semantics on ND-systems to qualify as meaning-conferring. There is also a proof-term assignment to NJ gderivations, materialising the Curry-Howard correspondence for this system.