The present invention relates to a multiply containerboard for use in corrugated board, said multiply containerboard comprising: a first outer ply comprising a strength enhancement agent, a second outer ply comprising a strength enhancement agent, and an interfacial layer joining said first and second outer ply, wherein each of said first and second outer ply comprise at least 50 wt % neutral sulfite semi chemical (NSSC) pulp based on dry weight, and wherein said interfacial layer comprises a strength enhancement agent in an amount of 0.5-20 gsm wherein the amount of strength enhancement agent in the interfacial layer is higher, preferably at least twice as high as the concentration of the strength enhancement agent in each of the first and second outer ply.