Ferry Oldenhof's Defence against 10-12 NT

Source: Dutch Bridge Magazine feb-oct 1979. Opponents open 10-12 NT:

• Double as takeout for majors
• Action after Stayman
• Action after 2D transfer
• Action after 2H transfer

Double

X takeout for majors or strong AQJx KQTx Jxx xx
                               AQJx Kxx KQTx xx
 -2C conv weak(less than 6,7), try to find fit 2-level
 -P minors okay, lead best major
 -2NT conf, game try
 -(2D)-X penalty
P with AQJx Jxx KQTx xx
       AKxx xx AKxxx xx vul (not vul: 2D)
       AQxx Axx Kxxx xx    
 -X also takeout
   ;2C weak
   ;2NT interested in game
   ;P-(2D)-P;X penalty
          -X maximum optional X

2C Stayman

P-(2C)-P;(2H)-P-X optional (strong, distributed), no good 4-crd C
                  AQx QJx AJxx QTx
                  Axx Kxx Axxx KJx
      -X good 4-crd, medium opening
        ;(2S)-P-X optional, and good 4-crd C
        ;(2H)-X cooperative - 9 hcp or 8 hcp w some H
                            - distributed
                            - no 4-crd C
                            - ex KJx Qxx Kxxxx xx
               -P w Axx QJx Axx HBxx
        ;P don't bid with good values: opportunity for penalty
          -(2H)-P;X cooperative
               -X optional

2D Transfer

P-(2D)-X medium opening, 4-crd D, distributional
        ;(2H)-X cooperative: 8-9, distr, max 3-crd D
               -P distributed AQx Txx AQTx Kxx
               -3D sound overcall: AJx xx AQJTxx Tx
               -2S 4/5-crd: AQTx xx AQxxx xx
               -3C 5-crd C, 4-crd D: xx xx AJTx AKJxx
               -2NT 5-crd D, 4/5-crd C possible
                    Ax xx AKJ9x QTxx or P
                    Ax xx AQJTxx Axx
                   ;3C Qxxx xxxx xx Qxx
                   ;3D-4C xx x AQJTx AKJTx
             -P-X optional with D
               -3S KJTxx x AKJTx Ax
               -3C 4-crd D, 5/6-crd C, competitive
             -2S nf
        ;P-(2H)-X optional
               -P;X cooperative
                   -3C Ax xx AQxx KJ9xx
               -3C with xx x AKJx KQTxxx
      -2S good suit
      -P;(2H)-P-2S JT9xx xx AQx KTx
                   AT9xx Qx KTx AJx
                   QJT9 xx KTx AJxx
                   QT9xxx x AJx Qxx
               -2NT unusual, not strong
               -X optional, not much in D
      -2H AQJxx xx AKx Kxx | too strong for 2S, or 4-crd S,
          AT9xxx x Ax AQJx | doesn't deny 4-crd D, when there is:
          AQJx Ax Qx HJxxx | - X to emphasize distribution
          AKTx x AKTx QT9x | - 2H to emphasize strength
          AT9x xx KJ AKQxx
          QTxxx x AKJx AQJ
          KT9xx x Axx AKQx
         -2S sign off, 3-crd S possible
         -2NT sign off, short S, less than 8 hcp
         -3C/D positive gf Kxx Qxx Kxx Txxx
         -3H gf in S
         -3S limit
         -3NT strong in H
         -4S end
      -2NT strong as cuebid, denies S: xx x AKJx AKJTxx
                                       xx x AKJTxx AKJx
                               but not xx x AKJTx AKJTx
          -3C negative
          -3D positive, 3-crd: AQxx Qxx Jxxx xx
          -3H positive in C: Axx Qxx xxx Qxxx
             -3S asks H-control
          -3S positive, 5/6-crd
          -3NT positive, good H-control, not interested in minors

2H Transfer

P-(2H)-X;(2S)-X-3C 4-crd H, long C
               -2NT;3C-3D length H, D second suit
               -3H sound overcall xx AQJxxx Axx xx
             -P-X optional with H
        ;P-(2S)-3C 4-crd H, possiblly 6-crd C
      -2S strong, 4+ crd H
         ;2NT weak, doesn't deny H
             -3C;3H weak w H
         ;3H invite
         ;3S strong, H is trump
         ;3D-3S no 5-crd H, waiting bid
      -2NT strong, maximum 3-crd H
          ;3C weak, nf
             -3D to play
          ;3S positive w C
          ;3NT good H-control, 4-crd C possible
          ;3H 5/6-crd H, positive
      -P;(2S)-P-X optional, no good 4-crd H