diff --git a/core/src/mindustry/io/JsonIO.java b/core/src/mindustry/io/JsonIO.java
index c612eccd13..56cc9bf4a9 100644
--- a/core/src/mindustry/io/JsonIO.java
+++ b/core/src/mindustry/io/JsonIO.java
@@ -20,11 +20,7 @@ import java.io.*;
 
 @SuppressWarnings("unchecked")
 public class JsonIO{
-    private static final CustomJson jsonBase = new CustomJson();
-
     public static final Json json = new Json(){
-        { apply(this); }
-
         @Override
         public void writeValue(Object value, Class knownType, Class elementType){
             if(value instanceof MappableContent c){
@@ -80,8 +76,9 @@ public class JsonIO{
         return json.fromJson(type, string.replace("io.anuke.", ""));
     }
 
-    public static <T> T read(Class<T> type, T base, String string){
-        return jsonBase.fromBaseJson(type, base, string.replace("io.anuke.", ""));
+    public static <T> T read(T base, String string){
+        json.readFields(base, new JsonReader().parse(string.replace("io.anuke.", "")));
+        return base;
     }
 
     public static String print(String in){
@@ -90,10 +87,9 @@ public class JsonIO{
 
     public static void classTag(String tag, Class<?> type){
         json.addClassTag(tag, type);
-        jsonBase.addClassTag(tag, type);
     }
 
-    static void apply(Json json){
+    static{
         json.setElementType(Rules.class, "spawns", SpawnGroup.class);
         json.setElementType(Rules.class, "loadout", ItemStack.class);
 
@@ -356,28 +352,4 @@ public class JsonIO{
             json.addClassTag(Strings.camelize(i.getClass().getSimpleName().replace("Filter", "")), i.getClass());
         }
     }
-
-    static class CustomJson extends Json{
-        private Object baseObject;
-
-        { apply(this); }
-
-        @Override
-        public <T> T fromJson(Class<T> type, String json){
-            return fromBaseJson(type, null, json);
-        }
-
-        public <T> T fromBaseJson(Class<T> type, T base, String json){
-            this.baseObject = base;
-            return readValue(type, null, new JsonReader().parse(json));
-        }
-
-        @Override
-        protected Object newInstance(Class type){
-            if(baseObject == null || baseObject.getClass() != type){
-                return super.newInstance(type);
-            }
-            return baseObject;
-        }
-    }
 }
\ No newline at end of file
diff --git a/core/src/mindustry/maps/Map.java b/core/src/mindustry/maps/Map.java
index c9767ca97f..0427d8f23b 100644
--- a/core/src/mindustry/maps/Map.java
+++ b/core/src/mindustry/maps/Map.java
@@ -100,7 +100,8 @@ public class Map implements Comparable<Map>, Publishable{
 
     public Rules rules(Rules base){
         try{
-            Rules result = JsonIO.read(Rules.class, base, tags.get("rules", "{}"));
+            Rules result = JsonIO.read(base, tags.get("rules", "{}"));
+
             //replace the default serpulo env with erekir
             if(result.planet == Planets.serpulo && result.hasEnv(Env.scorching)){
                 result.planet = Planets.erekir;