Video System's mahjong games cheats

[DracMonster]

You say you want to see naked anime girls? A noble ambition we should all aspire to. Video System's games seem to be impervious to winning hand cheats, so I came up with an alternate idea. With these, you just need to win or tie the girl once to get all her clothes. Not too hard if you buy all the extras with the infinite money cheats already in place. Incidentally, these should be easy enough to implement in the Visco games, too.

Code: Select all

;  [Video System "Final Romance" Mahjong Games]

:fromanc2:00000000:D88157:00000000:FFFFFFFF:CPU Cash Permanently 0
:fromanc4:00000000:80891D:00000000:FFFFFFFF:CPU Cash Permanently 0
:fromancr:00000000:D821BF:00000000:FFFFFFFF:CPU Cash Permanently 0

[DracMonster]

Whoops! Error! For Final Romance R, at least, the cheat doesn't seem to completely work right at higher levels. When I got to the gymnast girl, it gave her several million points somehow. More testing needed...

[DracMonster]

Yes, I am stupid for not realizing it would take multiple bytes to keep track of the scores. Go ahead and laugh. These work as far as I can tell:

Code: Select all

;  [Video System "Final Romance" Mahjong Games]

:fromanc2:00000000:D88156:00000000:FFFFFFFF:CPU Cash Permanently 0 (1/2)
:fromanc2:00010000:D88157:00000000:FFFFFFFF:CPU Cash Permanently 0 (2/2)

:fromanc4:00000000:80891C:00000000:FFFFFFFF:CPU Cash Permanently 0 (1/2)
:fromanc4:00010000:80891D:00000000:FFFFFFFF:CPU Cash Permanently 0 (2/2)

:fromancr:00000000:D821BE:00000000:FFFFFFFF:CPU Cash Permanently 0 (1/2)
:fromancr:00010000:D821BF:00000000:FFFFFFFF:CPU Cash Permanently 0 (2/2)

[Myrdred]

Drac, how about a few pointers for us mahjong novices on how to "win or tie" her?

I just started using the debugger, and I'm gonna try and break into the Video Systems driver games and create a win-the-hand cheat. It's been ages since I used assembly and I've never used 68000, but I'm making progress... a little, anyway

[DracMonster]

Well, I'll do my best. I'm going to make the assumption that you already know the rules and play of mahjong, and just want tips for beating the girls as quickly as possible. If you want a full explanation of how to play, say so and I'll give it a shot.

All the video system games let you buy advantages at the beginning. The most important one to get is the "lucky tiles" cheat. It is always the one that can be bought multiple times, which makes it more powerful. (All the games have infinite cash cheats, so go nuts.) This cheat will magically change the tiles to a mostly winning hand, usually just one or two short of what you need to win. The other important one is the "magic reach" which I'll explain below.

The honor tiles can be used to make higher scoring hands. However, in video mahjong, getting a high score doesnt really matter compared to getting a full winning hand as quickly as possible. Since the honor tiles are rarer, it takes longer to get a winning set of them, giving your opponent more time to complete her own hand. Thus, don't bother with honor tiles unless you are dealt a winning set at the start.

The x-ray vision cheat lets you see your opponent's tiles. This can let you see what she needs. Since you only have to get to the end of the hand without her winning, don't toss down a tile she needs, even if it's one that you don't.

The "magic reach": Reach (Default left shift in Mame) is used when you are one tile short of a winning hand. Once it is activated, you will not be able to throw back any of your tiles except the one you draw. If you get that winning tile, you get extra points. This is normally useless in video mahjong since getting a high score doesn't matter. HOWEVER, if you purchase the magic reach, it turns the next tile into exactly the one you need to win.

Hope these help.

[Myrdred]

Yeah, that helps quite a bit, thanks!

I'm not really very familiar with the rules of mahjong, but I have a basic idea. You want to make a hand with sets and/or runs of times, kind of like Gin Rummy with tiles instead of cards. And I was able to use that knowledge to win quite a few hands with your advice... but if you're willing to give a more complete description of the rules, I'd really appreciate it.

Any idea why these games are so resistant to winning-hand cheats? On some of them I've seen what look like two different copies in memory of the player's hand... but changing both of them didn't work. I'm wondering if maybe when you draw a tile, the game checks right then and there if your hand is winning (what's the difference between a tsumo and a ron?) and if so, sets a flag. Hmm... if that's the way it works, it may not be too difficult to find... just do a few "same" searches, then get a winning hand and do a "different" search. Maybe I'll try that...

(Myrdred wa hentai desu, ne?)

[stephh]

I'm not really very familiar with the rules of mahjong, but I have a basic idea. You want to make a hand with sets and/or runs of times, kind of like Gin Rummy with tiles instead of cards. And I was able to use that knowledge to win quite a few hands with your advice... but if you're willing to give a more complete description of the rules, I'd really appreciate it.

You're right : mahjong can be assimilated to gin-rummy ... This explains why there are so many variants (some mahjong games require less "skills" than others) ...

A good site IMO for mahjong rules is : http://members.aol.com/mahjongmuseum/tradrule.htm ...

This link is in MY WIP mahjong cheat database, and I suggest you to download it from my site (if you haven't already done so), so you'll be able to understand better the things I explain below ...

Any idea why these games are so resistant to winning-hand cheats? On some of them I've seen what look like two different copies in memory of the player's hand... but changing both of them didn't work. I'm wondering if maybe when you draw a tile, the game checks right then and there if your hand is winning (what's the difference between a tsumo and a ron?) and if so, sets a flag. Hmm... if that's the way it works, it may not be too difficult to find... just do a few "same" searches, then get a winning hand and do a "different" search. Maybe I'll try that...

The games with easiest cheats only test the 14 tiles in your hands ...

Some others (eg: 'mayumi') also check that the drawn tile is the same as your 14th tile ("tile N") ...

Some others (eg: 'janjans1') also use a byte (bit ?) to see that RON is possible ... This is because some combinaisons don't allow you to RON because you don't have enough "points" (= "specials" on some site) ...

The most complex ones ('mjyuugi*' and 'ponchin*') also check that the drawn tile matches one of the possible tiles expected to RON, so you have 4 other locations to check ...

Unfortunately, even with these known "tricks", I haven't been able to understand yet what was the scheme for the Visco/V System mahjong games But IMO, once such game is "done", I guess that it can be repeated for the others

Remember that the mahjong games are not so easy (even with the easiest settings), and it requires sometimes MANY games before you can beat the computer without cheating, so you can perform some "correct" searches, and then spot the differences between a hand where you can RON, and a hand where you can't ... And the fact that you have almost no possibility to get the SAME hand is more complicated to find the similarities

Last handicap (for me) : the Visco/V System mahjong games require sound to be run, so they are VERY slow on my P133 ...

Anyway, I don't despair in figuring out one day or another how a winning hand is coded, and how to have working cheats WITHOUT using ROM cheats ...

Steph from The Ultimate Patchers

Visit The Ultimate Patchers' site

[DracMonster]

Another little mystery... Often when I have what appears to be a winning hand, the game (not just the v system ones, any mahjong game) will not let me ron! This seems to happen when I have several sets made from the same suit. But not all the time. Is there a rule about what kind of sets you can win with or what? You mentioned that some specials don't have enough "points". What does that mean?

[kelvSYC]

Often in Mahjong, you can't win unless your hand is of some certain value. As I'm not familiar with the official Japanese rules (just familiar with the Hong Kong style), I can't tell you much.

Points are awarded based on the similarity of suits (more points for the same suit), the usage of dragon tiles (even for the pair), the usage of your own wind or the wind of the round, the similarity of sets (you get more if they are consistent), and the way you win (whether you pick it up yourself or pick it off someone else).

However, there is a maximum limit to the number of points that you can get (for determining the worth of unorthodox special hands and also so that you can't run away with the game after one round).

Example: you have a triple, a quad, a run (all of different suits), a non-significant wind triple, and a dragon (ie. you are looking for the dragon to win). Since your hand is worthless (although some variants might give some value to the quad), you can't win (it's illegal to win with a worthless hand) even with the matching dragon.

But if the triple, the quad, and the run were all of the same suit, it would be worth something (since winds and dragons don't count towards having a one-suit hand, but it would be worth even more if your hand had no winds or dragons), and you could win with it.

[Myrdred]

Thanks much for the info. I still have a tough time telling exactly what's a winning hand and what isn't, but that magic reach is great

I'm busy with other stuff right now so I've tabled my fiddling with the MAME debugger... I got as far as finding where in the game code the tsumo key was checked and was working on finding the code that's executed to determine if the tsumo is valid, but haven't found it yet.

Still dunno what the difference between tsumo and ron is...

[stephh]

Still dunno what the difference between tsumo and ron is...

I might be wrong, but I think one is when you finish your hand with the drawn tile, and the other when you finish your hand with the tile the CPU has just withdrawn ... If I'm correct, it's the same key in MAME (default 'Z') ...

Steph from The Ultimate Patchers

Visit The Ultimate Patchers' site

[DracMonster]

Example: you have a triple, a quad, a run (all of different suits), a non-significant wind triple, and a dragon (ie. you are looking for the dragon to win). Since your hand is worthless (although some variants might give some value to the quad), you can't win (it's illegal to win with a worthless hand) even with the matching dragon.

Ahhh, this clears so much up. I thought all sets scored, didn't know they could be worthless. And here I thought the computer was just cheating Armed with this info, I've found a new use for reach: most games won't let you use it unless you're about to win, so it can be a test to see if you're building a valueless hand. (Though good luck figuring out which sets to change.)