diff --git a/mappings/net/minecraft/registry/SimpleRegistry.mapping b/mappings/net/minecraft/registry/SimpleRegistry.mapping
index 9eb010f4e5..065a3012ea 100644
--- a/mappings/net/minecraft/registry/SimpleRegistry.mapping
+++ b/mappings/net/minecraft/registry/SimpleRegistry.mapping
@@ -16,6 +16,7 @@ CLASS net/minecraft/class_2370 net/minecraft/registry/SimpleRegistry
 	FIELD field_41126 key Lnet/minecraft/class_5321;
 	FIELD field_41127 wrapper Lnet/minecraft/class_7225$class_7226;
 	FIELD field_49135 keyToEntryInfo Ljava/util/Map;
+	FIELD field_51521 tagLock Ljava/lang/Object;
 	METHOD <init> (Lnet/minecraft/class_5321;Lcom/mojang/serialization/Lifecycle;)V
 		ARG 1 key
 		ARG 2 lifecycle