diff --git a/src/main/java/featurecat/lizzie/analysis/Leelaz.java b/src/main/java/featurecat/lizzie/analysis/Leelaz.java
index 29bab4450..d0a21a58e 100644
--- a/src/main/java/featurecat/lizzie/analysis/Leelaz.java
+++ b/src/main/java/featurecat/lizzie/analysis/Leelaz.java
@@ -34,6 +34,7 @@ public class Leelaz {
     private long maxAnalyzeTimeMillis;//, maxThinkingTimeMillis;
     private int cmdNumber;
     private int currentCmdNum;
+    private ArrayDeque<String> cmdQueue;
 
     private Process process;
 
@@ -72,7 +73,8 @@ public Leelaz() throws IOException, JSONException {
         isPondering = false;
         startPonderTime = System.currentTimeMillis();
         cmdNumber = 1;
-        currentCmdNum = -1;
+        currentCmdNum = 0;
+        cmdQueue = new ArrayDeque<>();
 
         JSONObject config = Lizzie.config.config.getJSONObject("leelaz");
 
@@ -182,7 +184,7 @@ private void parseLine(String line) {
                 // End of response
             } else if (line.startsWith("info")) {
                 isLoaded = true;
-                if (currentCmdNum == cmdNumber - 1) {
+                if (isResponseUpToDate()) {
                     // This should not be stale data when the command number match
                     parseInfo(line.substring(5));
                     notifyBestMoveListeners();
@@ -199,14 +201,16 @@ private void parseLine(String line) {
                 }
                 isThinking = false;
 
-            } else if (Lizzie.frame != null && line.startsWith("=")) {
+            } else if (Lizzie.frame != null && (line.startsWith("=") || line.startsWith("?"))) {
                 if (printCommunication) {
                     System.out.print(line);
                 }
                 String[] params = line.trim().split(" ");
                 currentCmdNum = Integer.parseInt(params[0].substring(1).trim());
 
-                if (params.length == 1) return;
+                trySendCommandFromQueue();
+
+                if (line.startsWith("?") || params.length == 1) return;
 
 
                 if (isSettingHandicap) {
@@ -278,11 +282,48 @@ private void read() {
     }
 
     /**
-     * Sends a command for leelaz to execute
+     * Sends a command to command queue for leelaz to execute
      *
      * @param command a GTP command containing no newline characters
      */
     public void sendCommand(String command) {
+        synchronized(cmdQueue) {
+            String lastCommand = cmdQueue.peekLast();
+            // For efficiency, delete unnecessary "lz-analyze" that will be stopped immediately
+            if (lastCommand != null && lastCommand.startsWith("lz-analyze")) {
+                cmdQueue.removeLast();
+            }
+            cmdQueue.addLast(command);
+            trySendCommandFromQueue();
+        }
+    }
+
+    /**
+     * Sends a command from command queue for leelaz to execute if it is ready
+     */
+    private void trySendCommandFromQueue() {
+        // Defer sending "lz-analyze" if leelaz is not ready yet.
+        // Though all commands should be deferred theoretically,
+        // only "lz-analyze" is differed here for fear of
+        // possible hang-up by missing response for some reason.
+        // cmdQueue can be replaced with a mere String variable in this case,
+        // but it is kept for future change of our mind.
+        synchronized(cmdQueue) {
+            String command = cmdQueue.peekFirst();
+            if (command == null || (command.startsWith("lz-analyze") && !isResponseUpToDate())) {
+                return;
+            }
+            cmdQueue.removeFirst();
+            sendCommandToLeelaz(command);
+        }
+    }
+
+    /**
+     * Sends a command for leelaz to execute
+     *
+     * @param command a GTP command containing no newline characters
+     */
+    private void sendCommandToLeelaz(String command) {
         if (command.startsWith("fixed_handicap"))
             isSettingHandicap = true;
         command = cmdNumber + " " + command;
@@ -298,6 +339,14 @@ public void sendCommand(String command) {
         }
     }
 
+    /**
+     * Check whether leelaz is responding to the last command
+     */
+    private boolean isResponseUpToDate() {
+        // Use >= instead of == for avoiding hang-up, though it cannot happen
+        return currentCmdNum >= cmdNumber - 1;
+    }
+
     /**
      * @param color color of stone to play
      * @param move  coordinate of the coordinate