Shirluban gave you the reason why. Here the problem is the 1-2-3 meld, that stops the hand from being all-singles (Assuming this particular game allows open-hand all singles, which is quite common). Also the ones in your hand, but at least these could still be changed to something else, but the one ...

Manzu chinitsu, dora 13. Kazoe yakuman. No? Well, it was worth a try...

Hindsight is 20/20, and sometimes, the tiles play trickster, and you got a second ryanwan (2c) right away. That being said, I'm no expert by any stretch of imagination, so take my advice with as many salt as you need, but I think in that situation I would have gone with the honitsu, if only because ...

Any one have some info on the steam game called "Mahjong Riichi Multiplayer"? It's for 9.99, so I only have seen the screenshots. One thing I didn't like it's in the screenshot where you can see a partial list, you see they've gotten for the "Closed +1" route, which we know it's ...

Yeah, the penalty is big, but it's there to discourage intentional false riichi. Of course, I understand the situation with your fellow player was not an intentional false riichi, but an inadvertant one. In this case, as shirluban said, you took the best option. If this is a very friendly play group...

At this point I would discard and the other one next round, and hope for a last tile win. Unlikely, but I am still positive points in a draw.

You have no yaku. That is the risk of opening your hand.

You found the answer already, but yes. The dora indicator is saying: "Add one han for each 5-pin in your winning hand". And the ura-dora indicator is saying: "Now add another han for each 5-pin in your hand". If the 5-pin were red (I don't know if you're using those), then, that'...

YOI KOKURISHIMUSOU MINNA-SAN!!!

I still have issue with the second of those combinations, but whatever. This is a game with multiple rule details to be set between the players.

You would have gotten Suu Ankou ONLY if you drew the white to call Tsumo. If calling ron, that triplet is considered open, and you get just Toitoi Sanankou (plus Shousangen. No dora because the kandora indicator wouldn't have been flipped).

Yeah, a noten riichi... That is weird. I'm not sure I like this rule. How does a hand become dead after riichi? Wrong number of tiles can't be the case, since you don't change the hand after the declaration... In any case, I would say that my hand becoming dead is my responsibility, and thus I shoul...

Wow, wow, wow... HOLD THE PRESSES!!!

Has no one noticed anything weird in E3-1??? Really??

But everyone was Tenpai, not Noten! You reached! And you know better than to do a noten riichi.

Something is not OK on this chart... East 1. Oya wins a small tsumo, North reached. East 1-1. South wins on oya's discard, with a riichi stick from West. East 2. Null hand. Presumably an exhaustive draw since there is a stick thrown from (original) East. All four players were tenpai. So far so good....