diff --git a/elasticsearch/src/main/java/org/elasticsearch/xpack/watcher/execution/Wid.java b/elasticsearch/src/main/java/org/elasticsearch/xpack/watcher/execution/Wid.java
index e0767daa9d0..a9378584eef 100644
--- a/elasticsearch/src/main/java/org/elasticsearch/xpack/watcher/execution/Wid.java
+++ b/elasticsearch/src/main/java/org/elasticsearch/xpack/watcher/execution/Wid.java
@@ -5,24 +5,35 @@
  */
 package org.elasticsearch.xpack.watcher.execution;
 
-import org.elasticsearch.common.UUIDs;
 import org.joda.time.DateTime;
 import org.joda.time.format.DateTimeFormatter;
 import org.joda.time.format.ISODateTimeFormat;
 
+import java.util.UUID;
+
 import static org.elasticsearch.xpack.watcher.support.Exceptions.illegalArgument;
 
+/**
+ * A representation class of a watch id, its execution time and a random UUID
+ * This class exists to be able to store several events from the same possible execution time and the same watch
+ * in the triggered store index or the history store
+ *
+ * One 'specialty' of this class is the handling of the underscore in the value. Nothing except the watchId should contain an
+ * underscore, otherwise this class will not be able to extract the proper watch id, when a a single string is handed over in its ctor
+ *
+ * This is also the reason why UUID.randomUUID() is used instead of UUIDs.base64UUID(), as the latter one contains underscores. Also this
+ * is not dependant on having time based uuids here, as the time is already included in the value
+ */
 public class Wid {
 
     private static final DateTimeFormatter formatter = ISODateTimeFormat.dateTime();
 
     private final String watchId;
-
     private final String value;
 
     public Wid(String watchId, DateTime executionTime) {
         this.watchId = watchId;
-        this.value = watchId + "_" + UUIDs.base64UUID().replaceAll("_", "-") + "-" +  formatter.print(executionTime);
+        this.value = watchId + "_" + UUID.randomUUID().toString() + "-" +  formatter.print(executionTime);
     }
 
     public Wid(String value) {