Niu Niu

That seems a long way to go around the problem. I'll check my pc and send the figures next time I'm on here.

I guess you meant the second bet is called double, ok.
I worked it out the following way.
Niu 6 comes every 6.468% hands, it wins 69.9155% of the time. That's against all smaller hands plus half of the niu 6 hands as against the dealer with niu 6 half will win and half lose.
That leaves you with a return of 4.522% of the hands that the house makes half a bet, so 2.26% house gains a full bet.
The other hands are irrelevant as simply coin toss.
I hope that helps.
If you need figures for the 5% tax I have them also.

I found a small error there. When the player has niu 6(1546 hands), the dealer will will also have niu 6 every 1546 times of the player occurrence. That is every 2390342 hands(0.004184%) they will both have niu 6. The player will win half of those so its:
Player gets niu 6 6.468%
Beats all hands not 5 and less
Plus half of the dual niu 6 hands (0.004184/2).
I make that 2.57344% house edge.
I wish the wizard would confirm or assist.
I did see his figures for no niu are different on his niuniu game description from those posted here. I think k the change would be minor for us normal folk so it's still a good game for a casino.