Gokō (五光) - Five Lights - 10pts
Shikō (or Yonkō) (四光) - Four Lights - 8pts
Ame-Shikō (雨四光) - Rainy Four Lights - 7pts
'Rain-man' (Poet) plus 3 other Lights.
'Ame' pronounced 'a-May' = Rain.
Sankō (三光) - Three Lights - 6pts
3 out of the 4 Lights that exclude the 'Rain-man' (Poet) - (November's Light card).
'Lights' are also known as 'Brights'.
Ino-shika-chō (猪鹿蝶) - Boar-Deer-Butterfly (BDB) - 5pts
The June, July and October 'Animal' cards.
1 additional point awarded for each extra 'Animal' card captured.
Tane (タネ) - Animals (literally 'Seed(s)') - 1pt
Also known as 'Tens'
Tane, pronounced 'Tan-A' = 5 'Animal' (10pt) cards that don't make the scoring hand of 'Ino-shika-chō' (see above).
1 additional point awarded for each extra 'Animal' card. These are also referred to as 'Earth' cards.
The 'Plank Bridge' and the 'Sake (Rice Wine) Cup' (both shown above) count as 'Animals'.
I prefer using the term 'Tens'.
Aka-tan (赤タン) - Red Poetry Scrolls - 5pts
Aka-tan, pronounced 'a-ka-tan'. All 3 Red Scrolls with Japanese script on them (the January, February and March Scroll cards).
1 additional point awarded for each extra 'Scroll' card captured. 'Aka' = Red.
Ao-tan (青タン) - Blue Scrolls - 5pts
Ao-tan, pronounced 'Ow-tan'. This hand is made up of the June, September and October Scroll cards.
1 additional point awarded for each extra 'Scroll' card captured. 'Ao' = Blue.
Note: Making both Ao-Tan and Aka-Tan [Aka-tan, Ao-tan no Chōfuku (赤短・青短の重複)]= 10pts, with 1 additional point awarded for each extra Scroll card captured.
A rule variant allows a player to make both Ao-tan (or Aka-tan ) and Tan. Example: Ao-tan plus 2 other scroll cards. This gives 5pts for Ao-tan and 1pt for Tan (6pts in total) rather than it counting as 5pts for Ao-tan plus 1pt for each additional scroll card for a total of 7pts.
Tanzaku/Tan (タン) - Scrolls - 1pt
Tanzaku, usually truncated to 'Tan' = 5 Scroll cards that do not make Ao-tan or Aka-tan.
1 additional point awarded for each extra 'Scroll' card captured e.g. 7 Scroll cards = 3pts.
'Scrolls' are also known as 'Strips' and even 'Ribbons' - despite them representing strips of paper.
Kasu (カス) - Dregs - 1pt
Kasu, pronounced 'Cass' = 10 'Dregs' cards.
1 additional point awarded for each extra 'Dregs' card captured e.g. 12 Dregs cards = 3pts.
Other names are 'Junk', 'Trash', 'Simples', 'Normals', 'Plains', 'Chaff' and 'Basics'.
Optional 'Viewing' Yaku
The following two hands are fairly easy to obtain and due to this they are not always included by players. One rule variant allows for their inclusion but the hands only count if another Yaku is made (simultaneously, subsequently or previously) e.g. Tsukimi-zake + Sankō; Hanami-zake + Tane; Tsukimi-zake + Hanami-zake + Kasu. Some scoring systems assign only 3pts for these 'viewing' hands.
Tsukimi-zake (月見酒) - Moon Viewing - 5pts
'Tsukimi' = Moon Viewing Festival. This hand consists of the August Light card (Harvest Moon) plus September's 'Sake Cup' card.
Hanami-zake (花見酒) - Blossom Viewing - 5pts
'Hanami' generally refers to Cherry Blossom Viewing. This hand consists of the March Light Card (Cherry Blossom with Viewing Curtain) plus September's 'Sake Cup' card.
Other scoring systems assign 15pts in total for capturing all three 'Viewing' cards - 'Viewing the Blossoms in the Moonlight'.
'Rain ruins the Party'
Another rule variant or how I like to call it 'Rainy day' as it looks better in Japanese (雨の日 - Ame no hi - 'wet day'); This rule disables the 'viewing' yaku for BOTH players if a November card is captured (variants being ALL November cards captured - which I prefer). I don't use it most the time but I think it's a fun rule.
Oya Gachi - 6pts
Another optional scoring rule is 'Oya-Gachi' (Dealer's privilege). This scores the 'Oya' (Dealer) 6pts in the event that no player makes a scoring hand during a round of a game (a variant includes the situation where one player has made a Koi-Koi call and then neither player is able to make a subsequent scoring hand).
Note: 'Oya' is the Japanese word for 'Parent' and in the work place it refers to the 'Boss' (who is usually an elder).
Dealt Hands (Instant Wins)
Here you win a round before a card is even played! These are rare.
Teshi (手四) - Four Hands - 6pts
Being dealt all 4 cards of the same suit.
Kuttsuki (くっつき) - Sticky - 6pts
Being dealt 4 pairs of cards of matching suits.
Other
The 'Sake Cup' card counts as both an 'Animal' and a 'Dreg' card e.g. if you have 9 Dregs cards and also have the 'Sake Cup' card you have made the yaku 'Kasu' worth 1pt. By the way, the character on the Sake Cup means 'Longevity'.
For any yaku made that is worth 7 or more points in total, then the score is doubled e.g. 8pts x 2 = 16pts. It is up to the players involved whether or not the doubling rule is used.
If 'Player A' calls 'Koi-Koi' and then 'Player B' makes a yaku and then 'Stops' (Shōbu), then 'Player B' doubles his/her score for that yaku.
Some rules allow for multiple 'Koi-Koi' calls and doubles (especially when playing for money), whilst others only allow for one per player per round.
Hiki
If three cards of the same suit are in the field of play then these are placed together. The player who has or draws the remaining card of that suit takes all three cards in one go when playing the remaining card of that suit.
Koi-Koi (こいこい) = 'Come Come' (as in 'carry/play on').
Shōbu (勝負) = 'Game' (as in the end of/conclusion of the match/bout/round/game).
Finally, it is worth remembering that there are practically as many different scoring systems for Koi-Koi as there are players. Families in Japan often pass down their own 'house rules' and Yaku values.