>Because there are fewer kinds of tiles, you can win on kanchan or penchan quite often.
>So if you reach tenpai in a yakuless hand and 1 dora, riichi even with kanchan or penchan.
>The downside of staying in yamiten to get a better wait is that it will take a few turns, and in those turns your opponents are not restricted in how they can advance their hands.
>By calling riichi, you restrict the others' movements and gain additional safety by slowing them down. Truly offence is the best defence.
TN: In the last two paragraphs he just repeats what he already repeated again so I'm not going to bother.