From Japanese mahjong wiki
The following is a number of select plays featuring shousangen.
|07-04-2014||Player: KyuuAA||Rank: 三段||Round: 南 1 局 0 本場|
|Source (Tenhou.net)||Natural damaten baiman hand with two triplets starting, with three types of sangenpai in the hand. Two types paired, while the third became a triplet.|
Hands with shousangen may often be tenpai for daisangen.
|11-14-2012||Player: KyuuAA||Rank: １級||Round: 南 3 局 1 本場|
|Source (Tenhou.net)||Natural daisangen opportunity as the three dragon types paired during development. Ron was called at the first opportunity.|
- Shousangen/Replays in Japanese Wikipedia