Folding Procedure (2)
If you are fully folding and run out of safe tiles,
you should keep discarding in order from lower danger to higher danger.
This means using your hand together with all four discard ponds to identify the tiles that are more likely to pass.
That, too, is part of reading.
Strictly speaking, mahjong waits come in only five forms:
ryanmen, kanchan, penchan, tanki, and shanpon.
So the fewer patterns a tile can deal into, the safer it is.
1. Hell Waits
After truly safe tiles, the next safest tiles are the ones that can only be hit in one single pattern.
For example:
- an honor tile when two copies are already visible on the table, so it can only hit a tanki wait
- the fourth
when all four copies of 
are visible, so it can only hit a penchan wait
These tiles are not absolutely safe,
but if you deal in on them, you just have to accept that it was bad luck.
A wait where there is only one possible hitting pattern left is called a hell wait.
Tiles That Can Only Hit Shanpon or Tanki
Once you no longer have comfortably safe tiles, the next tier is to look for tiles that can only hit shanpon or tanki waits.
Typical examples are:
- honor tiles
- suji terminal tiles
- no-chance terminal tiles
What these have in common is that they at least do not deal into ryanmen waits.
If one copy of such a tile is already visible on the table, the chance of a shanpon wait drops a bit further,
so it becomes somewhat safer.
There is also one very basic but important principle: delay cutting yakuhai as much as possible.
Even if they only hit shanpon,
if they do deal in, they often give the opponent an extra han, which usually makes the loss worse.
Tiles That Do Not Hit Ryanmen Waits
If the first two layers are gone, the player who is folding is already in a very uncomfortable position.
As explained earlier, the thing you should fear most against riichi is the ryanmen wait.
So at that point, the very least you should look for is a tile that does not deal into a ryanmen wait.
This includes:
- suji
- no-chance
2through8
At this stage, of course, there is no such thing as "comfortable defense" anymore.
It is just that if you must deal in, it is still better than dealing into the most common ryanmen shape.
At least then the opponent will not also get pinfu from that wait shape.
And among those tiles, you should still prefer the one with the lowest shanpon potential.
What to Do When Your Hand Is Completely Stuck
What if you have none of the three layers above in your hand?
Sometimes you can switch back to attack.
But in many cases, once your hand has already been broken apart this much, it is no longer in any shape to fight with.
In that case, the original page gives three emergency methods:
Method 1: Cut the Tile That Looks Even Slightly More Likely to Pass
For example:
- outer suji from tiles discarded early in the hand
- one-chance tiles
- any other weak safety clue you can extract through reading
In other words, keep reading and try to find a tile that is at least a little more likely to pass.
Method 2: Cut a Tile That Is Cheap Even If It Hits
For example, 1 and 9 tiles cannot give tanyao.
And no matter what, you should at least avoid tiles around the dora.
Method 3: Break a Pair or a Concealed Triplet
Rather than cutting several dangerous non-suji tiles in a row,
it is often safer to break apart a pair or a concealed triplet in your hand.
The idea is to pay one structural cost in your hand
in exchange for 2 to 3 turns of controlled retreat.
When it gets to this point, these are the kinds of measures you have to use just to scrape through.
Original Japanese page: http://beginners.biz/mamori/mamori07.html