So I've been messing around with redstone to try and understand how it works (extremely basic stuff like timing and whatnot) and I know about pistons having odd behavior where they get kinda powered but require a block update in actually work. But in this particular case there is nothing being updated so even if there is "quasi connectivity" it shouldn't make the pistons immediately extend. Would appreciate some explanation on whether this is intended or not and if it is indeed intended then why does it happen?

The image below is a simple way to test it and see for yourselves. enter image description here

  • It almost seems like the glass block is sending a block update somehow? But that doesn't make sense either so I don't know. Is this java or bedrock?
    – Unionhawk
    Dec 27, 2019 at 23:38
  • This is on 1.15.1 Java edition
    – SiMe
    Dec 27, 2019 at 23:39

1 Answer 1


It's called "bud-powering" or "quasi-connectivity" and it applies to pistons, dispensers and droppers.

The wiki says:

Quasi-connectivity is a property of dispensers, droppers, and pistons that allows them to be activated by anything that would activate the space above them, no matter what is actually in that space.

It's tricky to tell if it is a bug or intended feature but it's been in the game for a while and people have been using it in various redstone contraptions. This concept was also used to detect block updates before observers we're added into the game. You could say it's grown into a feature now. You can read more about "bud-powering" on the wiki: https://minecraft.wiki/w/Tutorials/Quasi-connectivity

  • Thanks for the answer! I tried this with a level as well and nothing happened. Do you have an idea why that would be different to a torch?
    – SiMe
    Dec 28, 2019 at 0:14
  • What did you mark the answer as accepted if it did not answer your question? Dec 28, 2019 at 1:29
  • @SiMe To answer that, one would have to explore the game code itself. Dec 28, 2019 at 1:38
  • It sounds to me like this only happens with redstone torches, no other power source. That would be a different issue. Also, the wiki calls itself "official", that's it. I think it means something like Gamepedia having multiple Minecraft wikis and that one being the preferred one or so. It's not owned, maintained or checked by Mojang. Dec 28, 2019 at 11:20
  • Quasi-connectivity is, itself, both a bug and a feature; it was initially a bug, but I believe it's a wontfix at mojang in order to prevent other block update based designs from breaking (including certain piston doors). That said I'm not certain this is the only thing that is happening here, but I haven't tested myself.
    – Unionhawk
    Dec 30, 2019 at 14:38

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .