World Riichi Championship Rules 2015 ～ Comments on the World Riichi Championship Rules 2015

2Glossary

WRC = World Riichi Championship
WRCC = World Riichi Championship Committee
WRCR = World Riichi Championship Rules
WRR = World Riichi Rules (aka WRCR)

2.1Terms related to groups

	Japanese		Meaning
Group	mentsu	面子	Group of three or four tiles. Either a chow, pung or kong.
Chow	shuntsu	順子	Group of three consecutive tiles of the same suit.
Concealed chow	anjun	暗順	Chow made with only self-drawn tiles.
Melded chow	minjun	明順	Chow made by calling a tile.
Chii	chii	チー	Declaration of calling a tile for making a melded chow.
Pung	kōtsu	刻子	Group or three identical tiles.
Concealed pung	ankō	暗刻	Pung made with only self-drawn tiles.
Melded pung	minkō	明刻	Pung made by calling a tile.
Pon	pon	ポン	Declaration of calling a tile for making a melded pung.
Kong	kantsu	槓子	Group or four identical tiles.
Concealed kong	ankan	暗槓	Kong made with only self-drawn tiles.
Melded kong	minkan	明槓	Either a big melded kong or a small melded kong.
Big melded kong	daiminkan	大明槓	Kong made by calling on a concealed pung.
Small melded kong	shōminkan	小明槓	Kong made by promoting a melded pung.
Kan	kan	カン	Declaration of making a kong (either melded or concealed).
Pair	toitsu	対子	Two identical tiles.

Concealed
A group is concealed if it is made by using only self-drawn tiles.

Melded
A group is melded if it is made by calling a tile.

2.1Terms related to groups

Please stop saying "concealed pon". "Pon" is what you say when making an exposed triplet, so "concealed pon" would mean "concealed exposed triplet", which doesn't make sense.

2.2Terms related to the whole hand

Tenpai
A player's hand is tenpai if it fulfils all these conditions:
1) The hand's 13 tiles needs only one more tile to form a complete hand of four groups and a pair, or seven different pairs, or the Thirteen Orphans yaku.
2) The completing tile must exist, even if it's not available.
A hand needing five identical tiles can never be completed, so it is not tenpai.
It does not matter if all completing tiles have been discarded, or are locked in other payer's hands, or are in the dead wall. Only the hand's 13 tiles are considered to determine if the hand is tenpai or noten.
3) The player is not under a "dead hand" penalty.

During the player's turn, the hand's 14 tiles is tenpai if it will fulfil the above conditions after discarding.

Noten
A hand is noten if it is not tenpai.

Winning hand
A player's hand is a winning hand if it fulfils all these conditions:
1) It has four groups and a pair, or seven different pairs, or the Thirteen Orphans yaku.
2) It has at least one yaku.

Tenpai
Examples of condition #2:
Noten:
1pin

This hand needs a 5th 1pin

to complete the pair, and nothing else, but there are only four in the tileset, so it is noten.

1sou

This hand could be competed with a 3sou

. Even if there is no 5th 3sou

, the

is still a valid wait, so this hand is tenpai.

9pin

(Another player has a South pon.)
Despite there is no south

available, this hand is still tenpai.
For determining if a hand is tenpai or noten, you should consider only the hand's tiles. Tiles locked into other players' melds and discarded tiles do not matter.

Closed
A hand is closed if it is made by using only self-drawn tiles, beside the winning tile.
If the hand is completed by calling a tile (ron), the last group or pair is melded but the hand is still closed.

Open
A hand is open if it is not closed.
I.e. a hand is open if it has at least one melded group before the winning tile.

Closed / Open VS Concealed / Melded
You may notice I used "concealed" / "melded" for groups and "closed" / "open" for hands (except for the "Fully Concealed Hand" yaku, due to historical reasons). This is supposed to help differencing those similar, yet different, concepts.

Edit 2016-10-28:
Actually, in a Fully Concealed Hand all groups are concealed, including the last group, so it follows the logic.

2.3Terms related to scoring

Yaku
A yaku is a scoring pattern.
Each yaku gives one or more han.

Dora
Each dora gives one han.

Han
One of the two scoring units used for evaluating the hand.
Earned from yaku and dora.

Minipoints / Fu
One of the two scoring units used for evaluating the hand.
Earned from groups, pairs and winning event.

Hanchan (sometimes called Session)
East and South rounds.

2.3Terms related to scoring

Hanchan score
After each hanchan, the "hanchan score" is calculated as follow, without rounding:
(points - 30,000) / 1,000 + uma

Overall score
For each player, the overall score is the sum of each hanchan scores.

Hanchan score
Remember the starting score for each hanchan is 30,000 points and there is no oka.
If for some reason you play with another starting score (missing sticks for your casual game?), don't forget to adapt the hanchan score calculation:
(points - starting points) / 1,000 + uma
Else, you'll screw the oka.