diff --git a/README.md b/README.md
index 246e5635..5410c0da 100644
--- a/README.md
+++ b/README.md
@@ -279,17 +279,6 @@ moment of adding them.
 { "foo,bar": ["baz"], "[object Object]": ["baz", "baz"] }
 ```
 
-Also, reading of properties on implicit block mapping keys is not supported yet.
-So, the following YAML document cannot be loaded.
-
-``` yaml
-&anchor foo:
-  foo: bar
-  *anchor: duplicate key
-  baz: bat
-  *anchor: duplicate key
-```
-
 
 js-yaml for enterprise
 ----------------------
diff --git a/lib/js-yaml/loader.js b/lib/js-yaml/loader.js
index ef01386b..d5bd1b45 100644
--- a/lib/js-yaml/loader.js
+++ b/lib/js-yaml/loader.js
@@ -991,6 +991,12 @@ function readBlockMapping(state, nodeIndent, flowIndent) {
       detected      = false,
       ch;
 
+  if (state.blockMappingEntry < state.position) {
+    state.anchor = _anchor = null;
+    state.tag = _tag = null;
+    state.position = state.blockMappingEntry;
+  }
+
   if (state.anchor !== null) {
     state.anchorMap[state.anchor] = _result;
   }
@@ -1292,7 +1298,8 @@ function composeNode(state, parentIndent, nodeContext, allowToSeek, allowCompact
       typeQuantity,
       type,
       flowIndent,
-      blockIndent;
+      blockIndent,
+      ch;
 
   if (state.listener !== null) {
     state.listener('open', state);
@@ -1321,6 +1328,7 @@ function composeNode(state, parentIndent, nodeContext, allowToSeek, allowCompact
     }
   }
 
+  state.blockMappingEntry = state.position;
   if (indentStatus === 1) {
     while (readTagProperty(state) || readAnchorProperty(state)) {
       if (skipSeparationSpace(state, true, -1)) {
@@ -1334,8 +1342,12 @@ function composeNode(state, parentIndent, nodeContext, allowToSeek, allowCompact
         } else if (state.lineIndent < parentIndent) {
           indentStatus = -1;
         }
+        state.blockMappingEntry = state.position;
       } else {
-        allowBlockCollections = false;
+        ch = state.input.charCodeAt(state.position);
+        if (ch === 0x7C/* | */ || ch === 0x3E/* > */) {
+          allowBlockCollections = false;
+        }
       }
     }
   }
@@ -1356,7 +1368,7 @@ function composeNode(state, parentIndent, nodeContext, allowToSeek, allowCompact
     if (indentStatus === 1) {
       if (allowBlockCollections &&
           (readBlockSequence(state, blockIndent) ||
-           readBlockMapping(state, blockIndent, flowIndent)) ||
+           readBlockMapping(state, state.blockMappingEntry - state.lineStart, flowIndent)) ||
           readFlowCollection(state, flowIndent)) {
         hasContent = true;
       } else {
diff --git a/test/samples-common/anchor-mapping-key.js b/test/samples-common/anchor-mapping-key.js
new file mode 100644
index 00000000..82cc0576
--- /dev/null
+++ b/test/samples-common/anchor-mapping-key.js
@@ -0,0 +1,7 @@
+'use strict';
+
+module.exports = {
+  foo:{
+    foo:'bar'
+  }
+};
diff --git a/test/samples-common/anchor-mapping-key.yml b/test/samples-common/anchor-mapping-key.yml
new file mode 100644
index 00000000..b22fa8e0
--- /dev/null
+++ b/test/samples-common/anchor-mapping-key.yml
@@ -0,0 +1,2 @@
+&anchor foo:
+  *anchor : bar
\ No newline at end of file
diff --git a/test/samples-common/tag-mapping-key.js b/test/samples-common/tag-mapping-key.js
new file mode 100644
index 00000000..38ebd93f
--- /dev/null
+++ b/test/samples-common/tag-mapping-key.js
@@ -0,0 +1,5 @@
+'use strict';
+
+module.exports = {
+  TRUE: 1
+};
diff --git a/test/samples-common/tag-mapping-key.yml b/test/samples-common/tag-mapping-key.yml
new file mode 100644
index 00000000..a3479a44
--- /dev/null
+++ b/test/samples-common/tag-mapping-key.yml
@@ -0,0 +1 @@
+!!str TRUE: 1
\ No newline at end of file
diff --git a/test/samples-load-errors/duplicate-anchor-key.yml b/test/samples-load-errors/duplicate-anchor-key.yml
new file mode 100644
index 00000000..7d146ebb
--- /dev/null
+++ b/test/samples-load-errors/duplicate-anchor-key.yml
@@ -0,0 +1,3 @@
+&anchor foo:
+  foo: bar,
+  *anchor: duplicate key
\ No newline at end of file