thanks everyone, I have made a mix from your suggestions: DBL = strong, any 16+ HCP, (first step negative response) 1S = natural (8-15 HCP, normal overcall) 1NT = 11-15, 5m+4M (2C=p/c, 2D=ask major, 2H=p/c) 2C/D/H = natural 11-15 (minor overcalls denies 4cM because of 1NT) in 4th pos: - after 1H - p - DBL=normal takeout to hearts, anything else natural - after (1H) - (1S = relay) - as above (strong double, 1NT=5m4M, 2x=natural) - after (1H) - (2 any = natural NF) - normal takeout doubles