A tad unconventional, but who can deny the playing strength of either hand?

2N 4S; 20-21 balanced // Optional keycard in Ds
5H 5S; 2 keys, no Q, accepting slam try // King ask
7N AKQJxx looks like enough

2NT? South only has 18 HCP.

This board fits our system like a glove.

N.       E.       S.        W

                     1      -

2    -          2     -

3    -          3     -

4    -          4     -

4    -          4N.      -

5    -          5     -

5    -          5N.      -

6    -          7N.      - 

-         -     

Where:

1 - <= 6 L 0 - 37 HCP any shape

2 - <= 8 L 5+. No 4M. If only 5 will have 4.

2 - Shape asking relay

3 - 6322 10 total losers

3 - Loser asking relay

4 - 6 L

4 - CROSS (colour, rank, opposite, same, same)

4 - 0 or 3 key card

4N - CROSS continuation K ask

5 - 0 or 3 K

5 - CROSS continuation Q ask

5 - 1 Q

5N  - Q suit ask

6 - Q

7N - to play

After North’s hand shape, 10 total losers, and 6 losers are revealed then from the rule of 18 a Grand Slam appears possible with North having 3 or 4 cards higher than a J from law of total losers. After North shows 3 A and Q South can count 16 tricks on top in NT if  and  break or 13 tricks if either  or  breaks so bids 7NT.