Mahjong Riichi Ippatsu

[Heike Fallago]

Whileippatsu is generally considered to be a standard yaku, certain rulesets do not use it, in order to reduce variance and lower the value of a riichii. In general, when sitting down to play a game, ippatsu is counted unless otherwise specified or agreed on before the game.

In order for ippatsu to be counted, the hand must win before the hand in riichi discards its next tile. The earliest possible chance to win with ippatsu comes from the shimocha's discard (player to the right). The latest possible chance to win with ippatsu is with the player's next drawn tile after the riichi declaration.

Furthermore, no interruption to the turn must occur. This means that tile calls will immediately end the chance for ippatsu. This includes any calls for kan except for a robbed kan (chankan). In sanma, the call for kita also denies ippatsu. If the riichi player declares kan or kita, ippatsu is still denied.

To repeat: even if a hand is won before the next discard, if a call is made, ippatsu is denied. Thus, players can purposefully make tile calls in order to disrupt another player's chance for ippatsu.

Unlike riichi, ippatsu cannot be combined with two yaku: rinshan kaihou and houtei raoyui. Rinshan requires a kan call (after declaring riichi), which would invalidate ippatsu. As for houtei, a riichi declaration must be made with at least 4 tiles left in the live wall. That leaves the very last possible tile draw (and discard) belonging to the riichi declarer.

The last possible chance for riichi comes when there are eighteen tiles left in the walls, counting the fourteen tiles in the dead wall. That leaves four tiles left for regular player draws. After the last possible riichi, if no tiles are called, every player would have exactly one tile draw left. Therefore, the last tile would go to the riichi declarer, allowing both ippatsu and haitei to be scored. Naturally, players may make tile calls to disrupt both yaku.

A note on some yaku combinations: It is possible to get ippatsu with Chankan (which will be discussed on a later day) if a player melds an added kan in the go around after you riichi. Since the kan was incomplete, the ippatsu is not cancelled. Also it is not possible to score rinshan kaihou (also to be discussed later) and ippatsu on the same hand. This would require you to draw a closed kan and then win on the supplemental draw. Even if you draw the kan on the go around after your riichi, it is still not technically considered ippatsu.

Ippatsu is a yaku that cannot be scored without riichi. It is the first of many luck based yaku that we will examine this month. To me, ippatsu is an exciting part of the game that can cause both unexpected surprises and upsets. Either way ippatsu further reminds us of the fact that mahjong requires both luck and skill to win.

Recently we have twice seen the situation where a player declares

riichi, the other players pick and discard once, and the

riichi-declaring player now picks a tile, declares concealed kan and

goes out on the lose tile. If anyone had declared a melded kan, pon or

chi, it would have ended the chance of Ippatsu. But how about a

concealed kan (nevermind which player declared it)? Does a concealed

kan ruin Ippatsu chances?Tina

>> Recently we have twice seen the situation where a player declares

>> riichi, the other players pick and discard once, and the

>> riichi-declaring player now picks a tile, declares concealed kan and

>> goes out on the lose tile. If anyone had declared a melded kan, pon or

>> chi, it would have ended the chance of Ippatsu.

Very interesting. Haven't seen that come up in Little Tokyo, and my friends

aren't very good at explaining things in English (or at listening to

detailed English questions), so I don't know what the most widely used

ruling would be. Of course there are so many different optional table rules

everyone uses everywhere... So the question is probably which way this'd be

ruled most often. When I can't find the answer locally, I usually email Ryan

in Japan. I'll give him a try.John continued:

>>After riichi declaration we allow the player to declare a concealed kan

>>if he later picks the forth tile, and if the hand is in no way changed

>>(the tiles could never be interpreted as anything but a pon/kan).

Ryan:

>If any player takes any action, including chi, pon, or kong, and including

>the reaching player, the chances for ippatsu have ended.

>

>Concealed kongs ruin ippatsu just like any other action.

>This includes a concealed kong on the first draw by the reaching player.My thanks to Ryan for the answer!

Cheers,

TomPS - Now to see what Nath wrote...

A Riichi hand is always revealed at the end of the play. No matter if

the Riichi is successful or not, the hand is and MUST be shown to apply

eventually penalties for false declaration of Riichi and altered hand.

Personally I dont see how any other solution can be found. The only

way to check to see if someone has a valid hand would be to have

everyone who riiches reveal their hand at the end of every round. This

would alter the strategy somewhat, as there are many pros who, even

though they are tenpai at the end of a round, will declare themselves

as no-ten because they do not want their opponents to see how they

played the hand. The same goes for the jansous, Id bet there are even

more non-pros who are so fussy about their playing style that having to

reveal their hand after every riichi might cause some to stop entirely.

Perhaps thats hyperbole, but Ive seen someone finish an East round

tenpai, declare no ten, and then finish second, behind the top guy by a

difference of 2000 points.The only thing that i think is missing out of the equation is the case

of player A making an invalid kan, flipping over a new dora tile, and

then player B winning with a hand that was made significantly more

expensive by the new kan dora. My guess is that those sorts of

situations dont really come up so often. After all, its pretty rare

that you even get the opportunity to make an invalid kan.-Benjamin Boas

Yeah, in all the Japanese mahjong video games that I've played on

various emulators (including MAME and N64), your hand is forced to be

revealed if you are Tenpai after a hand. You can't lie and say No-ten.

Sorry if I was a bit unclear. You make an invalid kan when, after you

riichi, you draw a tile (identical to three other in your hand),

declare a kan (and show all four identical tiles) but in doing so

change the wait pattern of your hand. As Ryan explains above, this is

may not affect the tiles you are waiting for, but is illegal

nonetheless (assuming you have to expose it).Youre correct in that all of the emulator games you are forced to

declare yourself tenpai if you are (although nantonaku ma-jan for

windows gives you a choice) but consider that in real life, how could

anyone possibly force you to expose a tenpai hand if they didnt know

you were tenpai in the first place?Addtionally, as Ryan reminds me right now, there are some (rare)

situations where it is advantageous to declare no-ten. Consider a case

in which you are in a close second place and the person in last has

barely any points. If you declare tenpai and do not gain enough points

to become 1st place, the person in last will run out of points and the

game will end with no chance for you to win. Considering that most

payment schemes in japanese mah jong heavily reward the person in 1st,

this situation is certainly possible.-Benjamin Boas

Seeing the writing on the wall, with their first place from the previous hanchan, Abraham smartly switches gears and looks towards a 2nd place to second their seat in the next round winning two back to back hands to put them in a comfortable 2nd.

In the Semi-Finals, Abraham is joined by Chiral, Ekusok and lostmyid (Jiemei). Riding the momentum from their performance in the first stage, Abraham launches a quick assault with two quick wins firmly seating them in their eventual victory.

After the previous hand Abraham went on to win several more hands including another mangan but also dealt into a mangan from Ekusok.

Entering South 3 Ekusok fires off an early riichi on turn 5. Feeling the groove Abraham riichis but traps themselves into a dangerous situation eventually dealing into an expensive Riichi Chiitoi Honitsu Ura2 for a dealer baiman reversal!

The second hanchan threatened Abraham with dying by a thousand cuts as they get pelted by tsumos and small rons from every player on the table. However A turn 9 Ippatsu Tsumo in East 3 begins their counter attack.

Entering their dealership in the South round, the game and by extension the title threatening to slip right through their hands, Abraham makes a bold riichi waiting on dora finding a quick ippatsu to reenter the race.

Again going cold, Abraham waits for their opportunity to strike which finally comes around in South 3 taking second row riichi. However in a bizarre turn of of events they face down a Toitoi hadaka tanki and a possible character Honitsu.

Thanking their lucky stars, Abraham draws their takame 6pin to convert on another 12000 points!

Once again falling to an early deficit, Abraham finds themselves in a pinch. South 1, last place 11400 points they begin their comeback with an absurdly quick Toitoi catching Ekusok who was trying to sakigiri dora by surprise.

Points are traded, hands go to ryuukyoku, the final hanchan proceeds to South 3, scores are tight, Abraham is in range but not quite there yet. Threading the needle they find a glorious 3 bamboo for an extremely important 2 han hand bringing them almost any win away from claiming the title.

FORTUNE SMILES UPON ABRAHAM, RYANMEN DOUBLE RIICHI. With an unbelievable Abraham fills their kanchan 46pin shape and proceeds to double riichi with the chance to end the game, the set, and the championship.

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