Rule presets

Japanese Modern

This rule preset represents a modern variation (Ari-Ari) of Japanese Mah Jong. As always in Japanese Mah Jong, only the winner receives payments, the discarder pays for all, and East receives and pays double. 

The rules differ from the classical Japanese rules mainly by acknowledging several additional bonus hands and patterns, further emphasizing the meaning of going out on a concealed hand, and by using Mangan scoring system with a settling table in determining the final score of the winner. The winning hand must be worth 1 han (without including extra han possibly earned by Dora tiles).

In addition, the rule of Ready (riichi) is used and the deal passes on draw unless the dealer has a ready hand (in Japanese classical rules deal always passes on draw). The rule of Missed discard is used, as in classical rules, and the rule of Sacred discard is used in its absolute mode, prohibiting a player from going out on any discard, if he has amongst his discards a tile, which would make his current hand complete (minimum point requirement is ignored in this situation). Furthermore, the ready players are paid after a draw, and any winner (not just the dealer) is paid for dealer's extra hands (and the pool is kept if the deal ends in a draw). 

The most distinctive feature of this rule preset is the use of Dora tiles, each giving an extra han to the winner. This feature emphasizes greatly the meaning of luck, and combined with severe discarder payments, gives these rules a strong gambling flavor.

Several different versions are played in Japan. E.g., Nashi-nashi rules are a stricter version of modern rules and differ from the more common Ari-Ari rules by rewarding points for All Simples only in a concealed hand (the rule is called Kuitan). In addition, Nashi-Nashi rules often apply stricter riichi rules, not allowing ready declaration on a sacred hand (Ari-Ari rules allow this, but the hand must go out self-drawn). You can easily create your favorite version by choosing Japanese Modern as your template and modifying the desired rule options.
Tiles 136 (no extra tiles)
Initial points 25,000
Limit points 2,000; the maximum final score determined by the settling table is 400% of the limit (though certain special hands may score even more).
Restrictions for the winning hand Minimum of 1 han.
Claiming rules for going out Multiple winners
Passing of the deal When non-dealer wins or deal ends in a draw (unless dealer has a ready hand)
Rule of Ready Rule of Riichi: voluntary declaration, concealed hand required (concealed Kongs allowed before the declaration), locked hand but non-altering concealed Kongs allowed, going out on first discard required; payment: 1,000 points (collected by the winner, retained in a pool in case the deal ends in a draw), 1 han if succeeded.
Dead hand rules Allow declaring of dead hand, if 9 or more different Terminals and Honors in the dealt hand; Abandon deal if four identical wind tiles discards on the first turn; Abandon deal if four Kongs declared during the deal; Abandon deal if 4 players have declared Ready. For more information, see Dead hand rules.
Payment To winner only; Japanese scheme; Payments for ready hands after a draw
Discards Per player with extended discard information
Specialties Dora tiles; Dealer's extra hands; Sacred Discard (Absolute); Missed Discard (Traditional)
Scoring Mangan system
Basic tile points Standard
Scores for basic sets Standard (han instead of doubles)
Scores for Flowers and Seasons Not used
Scores for patterns based on Chows Same Chow from all suits (1/2* han), Two identical Chows (0/1* han), 3 Chows of 1 suit, step 3 (1/2* han)
Note: * indicates scoring for the pattern in a concealed hand (winning tile can be a discard)
Scores for patterns based on Pungs and Kongs Three triplets of the same number (2 han), Three concealed triplets (2 han), Three Kongs (2 han), Little Three Dragons (4 han)
Note: * indicates scoring for the pattern in a concealed hand (winning tile can be a discard)
Scores for patterns based on the whole hand Concealed hand (10 fu), Fully concealed hand (1 han, forced scoring), No-points hand (10 fu / 1* han), Pung hand (2 han), Terminal or Honor in each set (1/2* han), Terminal in each set (2/3* han), All Terminals and Honors (3 han, Pung hand not implied), One suit with Honors (2/3* han), One Suit only (5/6* han) 
Note: * indicates scoring for the pattern in a concealed hand (winning tile can be a discard)
Scores for miscellaneous patterns None
Scores for winning Winning (20 fu),  Self-drawn last tile (2 fu), Out on a one-chance Chow (2 fu), Out on a pair (2 fu),  Out on the last tile of the Wall (1 han), Out on the last discard (1 han), Out on a supplement tile (1 han), Out by robbing a Kong (1 han), Declaration of Ready (1 han), Ready on first turn (1 han), Dora tile (1 han).
Rounding Rounding up to nearest before adding han multipliers and rounding up to nearest hundred at payment time
Penalties Faulty out: Deal ends and the offender pays 100% of Limit points to each of the other players, East receives, pays double (the deal is passed if the offender is East); Faulty Ready declaration: Deal ends and the offender pays 100% of Limit points to each of the other players, East receives, pays double; paid only if the deal ends in a draw; Faulty claims: 100 pts for each faulty claim, paid to the winner. In addition: each player who has declared ready without winning the deal must pay a penalty of 1,000 points to the winner of the deal; Insurance penalties: None
Limit hands Classical: All Green (400%), Four Kongs (400%), Hidden Treasure (400%, concealed Kongs allowed), Three Great Scholars (400%), Little Four Winds (400%), Big Four Winds (400%), All Honors (400%), All Terminals (400%), Nine Gates (400%), Nine Gates impure (400%), Thirteen Orphans (400%); Serpents: None; Pairs: Seven pairs (25 fu fixed + 2 han + cumulative han), Note: Identical pairs are not allowed; Special ways of going out: Heavenly hand (400%, supplement tiles are not allowed), Earthly hand (400%, narrowed interpretation: only for non-dealer going out on a self-drawn tile before any melds appear on the table); American hands: None; Miscellaneous: None.

Related topics:
Classification of rules
Alan's Zung Jung
American Classical
American Modern
British Official
Chinese Classical
Chinese New Style
Chinese Official
Chinese Transitional
Dutch League rules
EMA Riichi Rules
European Classical
Hong Kong Mah Jong
Internet Mahjong Server
Italian Official
Japanese Classical
Japanese Transitional
Korean Style
Mahjong Masters Million
Wilmington Advanced 12-Tile rules
WMPA Rules
Comparison table