Answer
Safe tile
Dangerous tile
Commentary
Meaning of discarding 2 in early round
The first three rounds of the game are very informative.
The meaning of discarding 2 is that
① Dosen't wait for 1-4m
②Very probable to have 5m
① depends on the round of call for Riichi.
In case discarding 2m at 2 round but calling Riichi at 4 round, 1-4m is dangerous.
This hand, ①+② → 4-7m or 3-6m is most dangerous.
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t's been raining again in Yokohama lately.
It's raining a lot this year.
I wonder if summer is over now and autumn is coming.
I'm a little sad.