Minecraft Wiki
Java Edition 15w34a.png


Release date

August 19, 2015

Snapshot for


Other editions of 15w34a
  • Computer

15w34a[1] is the tenth snapshot released for Java Edition 1.9.


Command format[]

NBT tags
  • Added the powered and conditional byte tags to Control tile entity for command blocks.
  • Added the life (Integer) and power (List/Double) tags to FireballBase.
  • Added the id string tag inside SpawnData for the MobSpawner tile entity.
  • Added the powered byte tag to Music tile entity for note blocks.



Command blocks
  • New textures that now vary depending on what direction they are placed from, similar to dispensers and pistons.
    • It consists of a front, a back and a side texture (looks like arrows), so the orientation can be easily determined.
    • The texture is animated - the colored "buttons" in the middle change color.
    • The middle panel texture has a black outline.
  • 3 modes: impulse, chain, and repeat - color changes based on mode.
    • Impulse mode (orange): Command is run once on rising edge.
      • Same behavior and color as previous versions.
    • Chain mode (green): Command is run whenever another command block pointing into it executes, and the command block in question is powered.
      • The chain signal is forwarded until the blocks get out of loaded chunks.
      • The signal is independent of the powered state of any block in the chain, as well as the command (or lack thereof) inside.
    • Repeat mode (blue): Command is run every game tick while powered.
      • Like a minecart with command block but faster.
    • Each new mode has its own block id and is obtainable with /give and pick block.
  • Power received is now a data tag, allowing command blocks to have such a state under control, independent of any nearby redstone signal.
  • Command block contraptions from earlier versions will still work.
  • The "Done" button is now always available to press, even when the command line is empty.
Note blocks
  • Their power state is controlled through a tag, and can, therefore, be controlled independently on any redstone signal.


  • Now start at a wider zoom level (1:4 instead of 1:1).
  • New recipe for zooming in on a map: Shears and a map together in any shape.
    • Zooms in on the lower-right quadrant of the original map.
    • This causes the shears to lose durability.


Zombies and zombie pigmen
  • Now lift their arms slightly when becoming hostile.

Non-mob entities[]

Minecarts with command blocks
  • The "Done" button is now always available to press, even when the command line is empty.

Command format[]

NBT tags
  • EntityId for the MobSpawner block entity has been deprecated.


  • New attack speed combat mechanic.
    • A meter shows up after switching items or attacking.
      • Damage done depends on the fullness of the meter.
      • Fills in 0.25s for non-weapons, 0.8s for swords, pickaxes, and shovels, and 1.2s for axes.
      • The meter can be displayed next to the hotbar (left or right based on the player's main hand), under the crosshair or turned off.
        • Looks like the icon for the strength effect on the side of the hotbar, or like a dagger under the crosshair.
        • This is controlled in video settings.
  • Delay when selecting a sword, pickaxe, axe or shovel into the main hand.


  • Optimized mob AI, pathfinding and block ticking.
    • 15% tick speed increase on 16 render distance.


7 issues fixed
From released versions before 1.9
  • MC-86152 – Records lose their custom name when placed in a record player.
From the 1.9 development versions
  • MC-83471 – "CustomPotionEffects" Inoperable with splash/lingering potions.
  • MC-84260 – Tipped arrows show no potion particles.
  • MC-85115 – Dragon fireball doesn't have a name (entity.DragonFireball.name).
  • MC-85592 – Default log4j2.xml is suboptimal.
From the previous development version
  • MC-86137 – Crash when breaking heads.
  • MC-86138 – Pick block on mob (dragon) head/structure block crashes the game.


Video made by slicedlime:


  • This version was previously removed from the launcher for some time, but was added back in September 2018.