Don’t discard 4s. 4 is bad. In Chinese and Japanese, 4 means death.
Not kidding here. Here’s why:
Hi, I’m Kastel. I’m dumb and don’t finish mahjong guides. I also don’t feel like screenshotting too. I just discarded a 4 bamboo. That means I can’t ron on 4 bamboo because that will be furiten. Well, everyone knows that. But here’s the catch: 1 and 7 bamboos are safe tiles. Under furiten rules, I won’t be able to chi nor complete 1-2-3, 2-3-4, 4-5-6, or 5-6-7. Because of 4 and furiten rules.
Remember: furiten applies because 4 connects all these sets. If you discard 4, you are immediately furiten for all these hands.
2-5-8 and 3-6-9 work the same way too.
What happens if I discard a 1? Then, 1 and 4 are the safe tiles. 7 isn’t because it isn’t connected to 1.
But in that scenario, I could also finish 3-4-5 or 4-5-6. It won’t be affected by the furiten rule.
So this is a rule-of-thumb of course. One can use this knowledge to troll players. Consider discarding a 4 if you’re waiting for a 1 or 7 to pop up because you have one of those and you need it to complete the hand as a pair.
I also discourage readers and players to discard 4, 5, and 6 because they give out a lot of information to mahjong players. Generally, it means you won’t be using the suit of the discarded tile. As I’ve said, 4 is a flexible number and you can connect a good number of sets with it. Lousy discards like these tell too much about the player. Also, people tend to aim for 4s and 5s to complete your hand. So unless you have to, don’t discard 4!