diff --git a/_test/test_bools.py b/_test/test_bools.py
new file mode 100644
index 0000000..d6620b3
--- /dev/null
+++ b/_test/test_bools.py
@@ -0,0 +1,77 @@
+
+import pytest
+import io
+import ruyaml  # NOQA
+from .roundtrip import round_trip, dedent
+
+from ruyaml import YAML
+from ruyaml.util import load_yaml_guess_indent
+from ruyaml.scalarbool import ScalarBoolean
+from ruyaml.comments import CommentedSeq
+from ruyaml.representer import RoundTripRepresenter, ScalarNode
+from ruyaml.constructor import RoundTripConstructor
+from typing import Text, Any, Dict, List  # NOQA
+
+
+def round_trip_stabler(
+    inp,
+    outp=None,
+):
+    if outp is None:
+        outp = inp
+    doutp = dedent(outp)
+    yaml = ruyaml.YAML()
+    yaml.preserve_quotes = True
+    yaml.preserve_bools = True
+    data = yaml.load(doutp)
+    buf = io.StringIO()
+    yaml.dump(data, stream=buf)
+    res = buf.getvalue()
+    assert res == doutp
+
+
+class TestStability:
+
+    def test_lowercase_boolean(self):
+        round_trip(
+            """
+        - true
+        """
+        )
+
+    @pytest.mark.xfail(strict=True)
+    def test_uppercase_boolean(self):
+        round_trip(
+            """
+        - True
+        """
+        )
+
+    # @pytest.mark.xfail(strict=True)  # Why not failing??
+    def test_yes_boolean(self):
+        round_trip(
+            """
+        - yes
+        """
+        )
+
+    def test_lowercase_boolean2(self):
+        round_trip_stabler(
+            """
+        - true
+        """
+        )
+
+    def test_uppercase_boolean2(self):
+        round_trip_stabler(
+            """
+        - True
+        """
+        )
+
+    def test_yes_boolean2(self):
+        round_trip_stabler(
+            """
+        - yes
+        """
+        )
diff --git a/lib/ruyaml/constructor.py b/lib/ruyaml/constructor.py
index 2c89807..104a090 100644
--- a/lib/ruyaml/constructor.py
+++ b/lib/ruyaml/constructor.py
@@ -75,7 +75,7 @@ class BaseConstructor:
     yaml_constructors = {}  # type: Dict[Any, Any]
     yaml_multi_constructors = {}  # type: Dict[Any, Any]
 
-    def __init__(self, preserve_quotes=None, loader=None):
+    def __init__(self, preserve_quotes=None, loader=None, preserve_bools=None):
         # type: (Optional[bool], Any) -> None
         self.loader = loader
         if (
@@ -91,6 +91,7 @@ def __init__(self, preserve_quotes=None, loader=None):
         self.state_generators = []  # type: List[Any]
         self.deep_construct = False
         self._preserve_quotes = preserve_quotes
+        self._preserve_bools = preserve_bools
         self.allow_duplicate_keys = False
 
     @property
@@ -1862,8 +1863,8 @@ def construct_yaml_timestamp(self, node, values=None):
     def construct_yaml_bool(self, node):
         # type: (Any) -> Any
         b = SafeConstructor.construct_yaml_bool(self, node)
-        if node.anchor:
-            return ScalarBoolean(b, anchor=node.anchor)
+        if node.anchor or self._preserve_bools:
+            return ScalarBoolean(b, anchor=node.anchor, orig_repr=node.value)
         return b
 
 
diff --git a/lib/ruyaml/main.py b/lib/ruyaml/main.py
index 4e54d2b..fd0a4fb 100644
--- a/lib/ruyaml/main.py
+++ b/lib/ruyaml/main.py
@@ -168,6 +168,7 @@ def __init__(
         self.prefix_colon = None
         self.version = None
         self.preserve_quotes = None
+        self.preserve_bools = None
         self.allow_duplicate_keys = False  # duplicate keys in map, set
         self.encoding = 'utf-8'
         self.explicit_start = None
@@ -242,7 +243,9 @@ def constructor(self):
         # type: () -> Any
         attr = '_' + sys._getframe().f_code.co_name
         if not hasattr(self, attr):
-            cnst = self.Constructor(preserve_quotes=self.preserve_quotes, loader=self)
+            cnst = self.Constructor(preserve_quotes=self.preserve_quotes,
+                                    preserve_bools=self.preserve_bools,
+                                    loader=self)
             cnst.allow_duplicate_keys = self.allow_duplicate_keys
             setattr(self, attr, cnst)
         return getattr(self, attr)
diff --git a/lib/ruyaml/representer.py b/lib/ruyaml/representer.py
index 5ce9855..d332e19 100644
--- a/lib/ruyaml/representer.py
+++ b/lib/ruyaml/representer.py
@@ -254,13 +254,16 @@ def represent_binary(self, data):
 
     def represent_bool(self, data, anchor=None):
         # type: (Any, Optional[Any]) -> Any
-        try:
-            value = self.dumper.boolean_representation[bool(data)]  # type: ignore
-        except AttributeError:
-            if data:
-                value = 'true'
-            else:
-                value = 'false'
+        if getattr(data, 'yaml_orig_repr', None) is not None:
+            value = data.yaml_orig_repr
+        else:
+            try:
+                value = self.dumper.boolean_representation[bool(data)]  # type: ignore
+            except AttributeError:
+                if data:
+                    value = 'true'
+                else:
+                    value = 'false'
         return self.represent_scalar('tag:yaml.org,2002:bool', value, anchor=anchor)
 
     def represent_int(self, data):
diff --git a/lib/ruyaml/scalarbool.py b/lib/ruyaml/scalarbool.py
index 8cae835..6da413b 100644
--- a/lib/ruyaml/scalarbool.py
+++ b/lib/ruyaml/scalarbool.py
@@ -18,10 +18,15 @@
 
 
 class ScalarBoolean(int):
+    yaml_orig_repr = None
+
     def __new__(cls, *args, **kw):
         # type: (Any, Any, Any) -> Any
         anchor = kw.pop('anchor', None)
+        orig_repr = kw.pop('orig_repr', None)
         b = int.__new__(cls, *args, **kw)
+        if orig_repr is not None:
+            b.yaml_orig_repr = orig_repr
         if anchor is not None:
             b.yaml_set_anchor(anchor, always_dump=True)
         return b