diff --git a/map/domon/gps-game.js b/map/domon/gps-game.js
index 1864f8b..1696d36 100644
--- a/map/domon/gps-game.js
+++ b/map/domon/gps-game.js
@@ -13,6 +13,9 @@
     var gpsmarker = L.marker(mymap.getCenter()).addTo(mymap);
     gpsmarker.bindPopup("STARTおしてね").openPopup();
 
+    var watchId = null;
+    var nTrial = 100;
+
     function getRandomPin() {
         return pins[Math.floor(Math.random() * pins.length)];
     }
@@ -27,9 +30,11 @@
 
     function tryWatchGPS() {
         stopGPS();
+        nTrial = 100;
         pinIndex = null;
         var pin1 = getRandomPin();
         var pin2 = getRandomPin();
+        pinIndex = Math.random() < 0.5 ? 0 : 1;
         document.getElementById("pin-info").textContent = `Pin 1: ${pin1.name}, Pin 2: ${pin2.name}`;
         watchId = navigator.geolocation.watchPosition(
             onSuccess, onError, { maximumAge: 0, timeout: 3000, enableHighAccuracy: true });
@@ -76,4 +81,4 @@
     document.getElementById("stop").addEventListener("click", stopGPS);
     document.getElementById("finish").addEventListener("click", finishGame);
 
-}, false);
+});