During the National, we constantly see how weak Kuro was, of how every important team knew of her ability and was not only able to stop her from winning, but to use her abilities to their advantage. To be fair, Kuro’s ability is pretty terrifying, and we saw how strong it was during the Nara Prefecture tournament (which was rushed through). Obviously, that huge advantage also made her hand way too predictable, something which was easily taken advantaged of once she started playing with good players. In the end of the anime series, we saw what she was did before, to throw away one of her dora’s to actually gain a victory…
Instead of talking about that play, lets talk about her abilities instead first:
At the start of any Japanese mahjong game, one dora indicator is shown, and hence four tiles (of the same thing) is the dora. Since Kuro has a very high chance of getting them, she can and will easily get 2-3 doras. Also, as she don’t want to throw them out, she will likely keep the doras for a pon or kan. By having a pon or kan in her hand would already mean that she can’t do pinfu, and if the dora is a wind, dragon, 1 or 9 or any suit, she can’t do a tan’yao also. She also can’t do chiitoitsu once she gets 3 doras [which is highly likely]. While this still leaves her with 9 more tiles to play with (assuming that she made a closed pon [ankō]) to something interesting, it makes her hand a bit more restricted already. On top of that we have the issue of…
Wow, this is the first time I think the red doras are annoying. As far as I remember, there are 2 red 5 pinzu, 1 red 5 sōzu, and 1 red 5 manzu. Now as those are doras, so Kuro will tend to collect them also. The issue for them is that, as listed, except for the 5 pinzu (she can keep both of them for eyes), all of them only comes in 1, so she must either find 2 non-dora 5 of the respective suit to form a pon, or form a chī (sequence) with 5 being one of the characters. Unless the tiles that she need is also a dora, her chances of finding them will not only be lower than her chances of getting a dora, but also lower than an average person, both because the probability of getting dora has increased, in the expense of the probability her getting any specific non-doras, and that each opponents will most likely be holding on to it knowing that she is looking for something near 5. On top of that, once she makes a chī (sequence), she can’t do toitoi, and since the red tiles are spread between the three suits, she can’t do hon’iisō or chin’iisō. With all those hands that she can’t do, she just can’t take the easy way out with something simple (for me) like toitoi, but has to do something funky like iipeikō or sanshoku, which, as far as I can tell, will limit her hand even more (especially if she is basing it around chī with 5 in it). Lastly, she can always try rīchi and/or tan’yao if possible.
Predicting the future
If what happened in chapter 9, around page 19-21 of the manga is not a fluke but a part of her ability, then I must say, it is something Kuro should have been taking advantage of as much as possible. In that scene, Champion did a closed kan, opened another dora indicator, and load and behold, Kuro’s hand suddenly had 3 more doras. Obviously Kuro shouldn’t know the 3 sou was a dora beforehand, but either by sheer luck/ability, the dora indicator went to the tile that she already have 3 of. This means that Kuro can actually guess what is the uncovered doras are (not really guess, but kinda have the ability to force it be something that her hand has). Again, if that wasn’t just a fluke, then there is a chance where she can just use her pure ability and obtain victory despite others trying block her.
Since chī requires the possession of three different tiles, it is not suitable for collecting doras, but instead Kuro should just go all pon/kan and do a toitoi, or even better, a san/sū kantsu. While this will make Kuro hand still very restricted, since she can’t throw out anything that is dora (even more as more doras indicators are flipped), and people might not kan precisely because of her strategy, but if she is really powerful enough, she will get all 4 dora, kan that and then 3 more of her tiles will become doras if she is doing toitoi. Also, she might be able to force the 5′s become dora, so she can just collect the 5′s on top of the red dora easily, and would not have to worry about just having 1 red dora without any connections. Just think of this, a sū kantsu with 18 doras, how awesome is that? Obviously there are way too many ifs and risks in this strategy, and she might never be able to do that in the end., and that some better mahjong players will come and complain at me of how futile/weak this is. Welp, I can only dream.
The other method
The more sensible method is to do what Kuro actually did by the end of the series, to actually throw away the dora and land a win. First, by doing that out of the blue, Kuro was able to surprise all her opponents, especially Champion. The excuse that Kuro used for not willing to throw any doras is that once she threw them, she won’t be getting any doras for a while. This raises the question of how long will she not get and doras and if the duration of her not getting doras is consistent or follows a function (ie not random). If the duration is not too long and the duration is also random, then Kuro can instead use that as an advantage and make her plays less random. If it is not long, then she might be able to regain her ability to get doras easily in the same game that she lost, and that the opponents might will less likely recognize that she lost her power to get dora’s before she regains them. Also since she is on the extreme end of either getting tons of doras and not throwing them out, and not getting any doras and hence can’t throw any out, her opponents can’t determine if she actually is holding doras just from her discard, and must depend on their own hand and the discards of others, which at times might be dora-less by coincidence, making the opponents less able to read her hand. Also, if the duration is random, the opponents cannot predict when she will regain her ability to get doras based on her previous plays. With the tactics of turning on and off her abilities, Kuro might actually start becoming a good player.