Answer July 9th 2019
Thanks for commenting! It wasn’t a non-trivial question…
The two most common answers were 6s or cutting the 12 group.
What did Tomotake do…
It was the 6!
I can understand the gut instinct to clear away that awkward wait. However, by cutting the 12 shape, you’re losing the ability to use a 3 of which there are four still out there. However, if you cut the 6, you’re only losing the ability to use another 6 if you draw it, and there are only two left out there anyway. So from the perspective of reducing the loss of tiles you can accept, 6 is an obvious discard.
The 12 may have been a better choice if this hand had anymore obvious value and/or you have time to work it into that shape with value. But Tomotake is the dealer here. He wants to go fast and get another turn at dealer.
This was the final shape. Another thing worth noting is how long he held on to that isolated dora. “Dora is your lover” is a mantra often heard from Aki Nikaido. I would have been tempted to clear it out when the player to my left threw it to ensure I wasn’t left with a dangerous tile. However, it could have also easily ended up with me drawing another and regretting everything.
Thanks for commenting, guys! I super appreciate not talking to myself <3