I’ve noticed that when I have a hand of all doubles and one single, as well as one extra tile which I am discarding (in this case, it would be the extra “one” tile as shown in the picture below), I’m unable to declare riichi. As far as I know, seven pairs is a yaku, so once I draw that five, I should be able to declare riichi, right?

Thanks for any help and thanks for running such an amazing site!

It is an implementation bug!