{{Infobox version
|title=Minecraft 18w09a
|edition=Java
|image=18w09a.png
|image2=Java Edition 18w09a.png
|type=Snapshot
|date=March 1, 2018
|parent=1.13
|clienthash=701085c1b668d45b7c0ee5ea911b11d6691c01bc
|jsonhash=2363421af13b87a427a32273f733f628db3bc262
|serverhash=57dd2fe4a2fdb6e846b978e77442465d2ea27f43
|prevparent=1.12.2
|prev=18w08b
|next=18w10a
|nextparent=1.13.1
}}<onlyinclude>

'''18w09a''' is the twenty-third [[snapshot]] for [[Java Edition 1.13]], released on March 1, 2018<ref>{{snap|18w09a|March 1, 2018}}</ref>, which added [[coral block]]s and [[underwater ruins]].

== Additions ==
=== Blocks ===
; {{Animate|Tube Coral Block JE1.png; Brain Coral Block JE1.png; Bubble Coral Block JE1.png; Fire Coral Block JE1.png; Horn Coral Block JE1.png|32px}} [[Coral block]]s
* Come in 5 colors: blue, pink, purple, red, yellow.
* Turn into dead coral when placed out of the water.
** Dead coral cannot be revived.
* Only obtainable in the Creative inventory.

=== World generation ===
; {{EnvLink|Underwater ruins}}
* Come in many different shapes and sizes.
* Cold ruins can be found in cold and frozen ocean biomes regardless of depth.
* Warm ruins can be found in warm, lukewarm, and deep lukewarm ocean biomes.
* Can generate alone or as part of a big ruined village.
** Can also generate out of the water, slightly underground or slightly above sea level.

== Changes ==
=== Mobs ===
; [[Phantom]]s
* No longer spawn in the End.
* Now despawn during daytime.

=== Command format ===
; [[Tag]]s
* Added the vanilla block and item tag <code>minecraft:coral</code>.
* The <code>minecraft:water_hacked</code> tag now includes [[chest]]s.

=== General ===
; Optimizations
* Optimized particle rendering slightly

== Fixes ==
{{fixes|fixedin=18w09a|prefix=Minecraft
|;old
|118324|One of magenta dye recipes is unlocked via getting Ink Sac
|118416|Recipe for bowl not unlocked until bowl or mushrooms are obtained
|;dev
|125141|Witch huts generated by new world generator don't spawn witches
|125451|Crash when logging into multiplayer without logging into singleplayer first
|;previous
|126150|Furnaces don't account for multiple recipes with the same output when giving experience and smelting recipes
|126111|Furnaces don't award recipes or experience when output is taken after a reload
}}</onlyinclude>

== Video ==
Video made by [[slicedlime]]: 
{{yt|SYVIHsEDkPI}}

== Trivia ==
* Unlike most of the first-of-the-week snapshots, this was released on a Thursday instead of Wednesday, similar to the snapshots before [[14w26a]].
* 18w09a was released exactly 6 years after [[Java Edition 1.2.1|1.2.1]] and [[Java Edition 1.2.2|1.2.2]].

== References ==
{{reflist}}

== Navigation ==
{{Navbox Java Edition versions|1.1x}}

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