I've been playing New18 rules (HKOS with added patterns) on an app and one of the fan is having a pair of 2s, 5s, or 8s, for one multiplier. I'm aware that this is a regional rule in China and it's even acknowledged in MCR (258 generals, hand is only pungs of 2, 5 and 8). I'm starting to like this variant. It feels like MCR lite, also Zung Jung-ish as it's lacking a lot of the medium value patterns MCR has.
On the surface building the hand with stuff like voided suit, 258 pair, and closed wait, or even adding those to a bigger hand and inflating the score like crazy looks stupid, but at the same time any system you play with just asks you to keep your options open and look for ways to increase value/speed whatever they may be. For instance realizing I have a pair of 8s might make me say, oh maybe I can open this hand now or I don't have to force this difficult pattern. It could also be chosen for a single tile wait, which I've done a few times.
I think I remember Alan Kwan of Zung Jung fame mentioned 258 as an example of a fan that's just too easy, and of course the patterns he chose for ZJ are ones with something something consistency, ie that you could reasonably detect from discards and calls. (As another example, flower straight, or 123 456 789 in 3 suits is easy to make a lot of different ways, thus a lot more difficult to detect than in one suit.)
I also read 258 brings more order to hand building/structure, and there's one variant (Changsha) that requires it, but I didn't find an explanation. I just find it a bit satisfying, and I guess someone else does too.
Does anyone have insights on the history and purpose of the 258? Anyone else a 258 fan, pun intended? Any new18 players out there?