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I have been reading a series of articles online regarding defense theory.
http://www.google.com/url?sa=t&rct=j&q= ... Ww&cad=rja
I came across this statement:
"As there will be more points from waiting on the dora, waits on the dora can be predicted. When the dora is chunchan, the deal-in rate is 1.5-1.6 times of the normal rate, while when the dora is a yaochuhai, the deal-in rate increases to 1.8-1.9 times"

Now if chunchan means the middle tiles of 2-8, and yaochuhai is the terminal and honor tiles, what exactly is the "normal" rate that these are being compared to?
Assuming these are correct definitions, what am I missing here?

Also, what is meant by riichi nomi and riichi domi?
Have seen "nomi" before other terms like pinfu, chun, etc, but only once was there any sort of definition, and that was "same value". Can anyone clarify?

I have these numbers from a document of unknown validity:

Chances of dealing into riichi:
Genbutsu (guaranteed opponent's furiten): 0%
Wind or dragon tanki (when you see three of them): 0,9%
Suji 1, 9 (when the opponent is in guaranteed furiten for 4 or 6 respectively): 2,9%
Wind or dragon tiles (when you see less than 3): 3,4%, but these may increase the opponent's hand value
Suji 2, 8: 4,8%
Suji 3, 7, or 4, 5, 6 with 2-sided suji: 5,5%
1 or 9 without suji: 6,3%
2, 3, 7, 8 without suji, or 4, 5, 6 with 1-sided suji: ~7%
4, 5, 6 without any suji: 12,3%

But as far as the linked article goes, it tells you to treat the dora as 2/3 grades more dangerous.

Nomi means only. So an X nomi is a hand with no yaku besides X and no dora.

Got this out of that online strategy primer book.

Assume that you are the North player in the 6th turn in South-4. You are currently ranked second, and the first ranked player (South) has 3300 more points.


The dora is the and you draw a

You wanted to draw a first so that you can have riichi + pinfu + one dora = 3900. Winning that hand by ron from anyone would improve your placement. However,
now that you drew a , what should you do?

I'm having a brain drain. I don't see how you can get riichi/pinfu/dora for 3900 pts. (30fu-3 han)
If you tsumo, it's 20fu-4 han for 5200 pts. (adding CSD to riichi/pinfu/dora)
If you ron, it's 30fu-2 han for 2000pts. (pinfu yaku does not count anymore, right?)
That would also mean that you can't improve your placement by a ron from ANYONE, only from the leader, South. (you get 2000, he loses 2000).
Am I overlooking something? I did go back to review that lengthy open pinfu discussion.
http://reachmahjong.com/en/forum/viewto ... mbo#p58728

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Incidentally, for that last "What Should You Do" part, it recommends calling riichi and discarding the dora for a ryanmen wait. Is that better than taking the risk by keeping the dora and tossing the for a kanchan wait?

a) Kanchan : riichi + dora. Ron : 2 han / 40 fu - 2600, first place guaranteed only on a direct ron from the South ; tsumo : 3 han / 30 fu - 1000/2000, first place. Up to 4 tiles available.
b) ryanmen : riichi + pinfu. Ron : 2 han / 30 fu - 2000 points, first place guaranteed only on a direct ron from the South ; tsumo : 3 han / 20 fu - 700 / 1300, first place (only by 100 points but whatever). Up to 8 tiles available.

Sure, the pinfu hand is a bit cheaper, but both hands are equally good when it comes to the points for a guaranteed first place, and the pinfu hand has twice as many winning tiles. If you're willing to put into balance the possibility of ura/ippatsu, then both would allow you to take a ron from the two other players (a becomes 5200 and b becomes 3900), so there again both are equally good in terms of points

The only case the a) hand would guarantee you a first place where the b) wouldn't is if another player declared riichi (+1000 in the balance) but that's even more far-fetched than ura/ippatsu. So overall that should be a no-brainer: go for the wait with the better odds!

or2az wrote:I don't see how you can get riichi/pinfu/dora for 3900 pts. (30fu-3 han)
If you tsumo, it's 20fu-4 han for 5200 pts. (adding CSD to riichi/pinfu/dora)
If you ron, it's 30fu-2 han for 2000pts. (pinfu yaku does not count anymore, right?)

It does. You can win pinfu by ron.
Riichi + pinfu + dora + ron = 3-30 = 3900

or2az wrote:Incidentally, for that last "What Should You Do" part, it recommends calling riichi and discarding the dora for a ryanmen wait. Is that better than taking the risk by keeping the dora and tossing the for a kanchan wait?

It's "riichi + pinfu with 8 live tiles" VS "riichi + dora with 4 live tiles": same value but twice more chances to win.
Of course, IRL you should worry other players might want a dora, and also check are not depleted.

Thanks guys. Sorry to put you through all of that. Like I said, brain drain.
I had it in my head that since Pinfu is awarded for a hand which scores no extra fu points on top of those received for winning and since menzen ron gives 10 extra fu points on top of the 20 for winning, that the pinfu yaku wasn't valid anymore.
I Should Have Known Better. (and went to sleep earlier)