diff --git a/core/assets/bundles/bundle.properties b/core/assets/bundles/bundle.properties
index f43517e27c..2456397a90 100644
--- a/core/assets/bundles/bundle.properties
+++ b/core/assets/bundles/bundle.properties
@@ -1063,6 +1063,7 @@ rules.unitcapvariable = Cores Contribute To Unit Cap
 rules.unitcap = Base Unit Cap
 rules.enemycorebuildradius = Enemy Core No-Build Radius:[lightgray] (tiles)
 rules.wavespacing = Wave Spacing:[lightgray] (sec)
+rules.initialwavespacing = Initial Wave Spacing:[lightgray] (sec)
 rules.buildcostmultiplier = Build Cost Multiplier
 rules.buildspeedmultiplier = Build Speed Multiplier
 rules.deconstructrefundmultiplier = Deconstruct Refund Multiplier
diff --git a/core/assets/maps/onset.msav b/core/assets/maps/onset.msav
index 7916e15b77..4a60322380 100644
Binary files a/core/assets/maps/onset.msav and b/core/assets/maps/onset.msav differ
diff --git a/core/src/mindustry/core/Logic.java b/core/src/mindustry/core/Logic.java
index 0a0ce51f2a..08df9cfeec 100644
--- a/core/src/mindustry/core/Logic.java
+++ b/core/src/mindustry/core/Logic.java
@@ -168,7 +168,7 @@ public class Logic implements ApplicationListener{
     public void play(){
         state.set(State.playing);
         //grace period of 2x wave time before game starts
-        state.wavetime = state.rules.waveSpacing * 2;
+        state.wavetime = state.rules.initialWaveSpacing <= 0 ? state.rules.waveSpacing * 2 : state.rules.initialWaveSpacing;
         Events.fire(new PlayEvent());
 
         //add starting items
diff --git a/core/src/mindustry/game/Rules.java b/core/src/mindustry/game/Rules.java
index 7289947532..c86ebee88d 100644
--- a/core/src/mindustry/game/Rules.java
+++ b/core/src/mindustry/game/Rules.java
@@ -81,6 +81,8 @@ public class Rules{
     public float dropZoneRadius = 300f;
     /** Time between waves in ticks. */
     public float waveSpacing = 2 * Time.toMinutes;
+    /** Starting wave spacing; if <0, uses waveSpacing * 2. */
+    public float initialWaveSpacing = 0f;
     /** Wave after which the player 'wins'. Used in sectors. Use a value <= 0 to disable. */
     public int winWave = 0;
     /** Base unit cap. Can still be increased by blocks. */
diff --git a/core/src/mindustry/ui/dialogs/CustomRulesDialog.java b/core/src/mindustry/ui/dialogs/CustomRulesDialog.java
index 271d80d2a2..355654bddb 100644
--- a/core/src/mindustry/ui/dialogs/CustomRulesDialog.java
+++ b/core/src/mindustry/ui/dialogs/CustomRulesDialog.java
@@ -141,6 +141,10 @@ public class CustomRulesDialog extends BaseDialog{
         check("@rules.wavetimer", b -> rules.waveTimer = b, () -> rules.waveTimer);
         check("@rules.waitForWaveToEnd", b -> rules.waitEnemies = b, () -> rules.waitEnemies);
         number("@rules.wavespacing", false, f -> rules.waveSpacing = f * 60f, () -> rules.waveSpacing / 60f, () -> true, 1, Float.MAX_VALUE);
+        //this is experimental, because it's not clear that 0 makes it default.
+        if(experimental){
+            number("@rules.initialwavespacing", false, f -> rules.initialWaveSpacing = f * 60f, () -> rules.initialWaveSpacing / 60f, () -> true, 0, Float.MAX_VALUE);
+        }
         number("@rules.dropzoneradius", false, f -> rules.dropZoneRadius = f * tilesize, () -> rules.dropZoneRadius / tilesize, () -> true);
 
         title("@rules.title.resourcesbuilding");