Forcing pass and other interesting auctions

Colin, Ray and I have some basic rules like a pass is forcing if we have bid a vulnerable game except if one partner has preempted (and his partner hasn’t shown extra strength).  A number of questionable situations came up today.  Here is one we discussed.  I am interested in your thoughts.

We were red on white.

East opened 1D and South (me) passed.  West bid 3D (preemptive) and Colin doubled.  East bid 4D and I bid 4H.  Now West bid 5D.  Are we in a forcing pass situation?

I thought that we were because we had voluntarily bid a vulnerable game after Colin showed strength.  Colin thought that my pass had shown weakness, although in later discussion we agreed it hadn’t.

As it turned out we did the right thing (doubling them).

It didn’t take long before another forcing pass problem arrived. 

Once again we were vulnerable against not and we voluntarily bid game.  Since Colin had passed he had more shape than cards and I had passed 1D.  But my pass of 1D didn’t show a weak hand (just no sensible bid).  What do you think?  If you assume that at these colours Colin should have a good hand then perhaps it should be forcing.  Anyway once again we doubled and it was right but I am still not sure about this one.

We did agree that this auction was not a forcing pass situation.

This time you are white on red.  Colin did show strength by doubling and I think I showed some cards when I bid 3C but at this vulnerability I don’t need all that much (except 5 clubs). 

Now here is one where you have to guess the trump suit.  You have S 8 H KQ10942 D J86 C AJ4

Playing standard you open 1H and partner bids 2C.  RHO bids 2S and you bid 3H.  Partner bids 3S.  Is partner looking for a spade stopper or does partner have hearts.  It just isn’t clear.  Now you bid 4C.  Does this just show club cards or does it show support?  I didn’t really care on this hand.  LHO now bids 4S and partner bids 4NT.  What is the trump suit? 

I think it has to be hearts.  I don’t think partner was looking for notrump any more.  His spade had to be a cuebid.  Anyway Colin didn’t take a chance and just bid 6H which was cold.

It seems to me that you can get a lot of this type of ambiguous auction in slam auctions.