Index: abstract.c
===================================================================
--- abstract.c	(revision 62102)
+++ abstract.c	(working copy)
@@ -2940,6 +2940,12 @@
 	return recursive_isinstance(inst, cls, Py_GetRecursionLimit());
 }
 
+int
+PyObject_RealIsInstance(PyObject *inst, PyObject *cls)
+{
+	return recursive_isinstance(inst, cls, Py_GetRecursionLimit());
+}
+
 static  int
 recursive_issubclass(PyObject *derived, PyObject *cls, int recursion_depth)
 {
@@ -2990,6 +2996,12 @@
 }
 
 int
+PyObject_RealIsSubclass(PyObject *inst, PyObject *cls)
+{
+	return recursive_issubclass(inst, cls, Py_GetRecursionLimit());
+}
+
+int
 PyObject_IsSubclass(PyObject *derived, PyObject *cls)
 {
 	static PyObject *name = NULL;
Index: typeobject.c
===================================================================
--- typeobject.c	(revision 62102)
+++ typeobject.c	(working copy)
@@ -572,6 +572,55 @@
 	return result;
 }
 
+extern int
+PyObject_RealIsInstance(PyObject *inst, PyObject *cls);
+
+static PyObject *
+type___instancecheck__(PyObject *type, void *inst)
+{
+	switch (PyObject_RealIsInstance(inst, type)) {
+	case -1:
+		return NULL;
+	case 0:
+		Py_RETURN_FALSE;
+	default:
+		Py_RETURN_TRUE;
+	}
+}
+
+
+static PyObject *
+type_get_instancecheck(PyTypeObject *type, void *context)
+{
+	static PyMethodDef ml = {"__instancecheck__",
+				 type___instancecheck__, METH_O };
+	return PyCFunction_New(&ml, type);
+}
+
+extern int
+PyObject_RealIsSubclass(PyObject *inst, PyObject *cls);
+
+static PyObject *
+type___subclasscheck__(PyObject *type, PyObject *inst)
+{
+	switch (PyObject_RealIsSubclass(inst, type)) {
+	case -1:
+		return NULL;
+	case 0:
+		Py_RETURN_FALSE;
+	default:
+		Py_RETURN_TRUE;
+	}
+}
+
+static PyObject *
+type_get_subclasscheck(PyTypeObject *type, void *context)
+{
+	static PyMethodDef ml = {"__subclasscheck__",
+				 type___subclasscheck__, METH_O };
+	return PyCFunction_New(&ml, type);
+}
+
 static PyGetSetDef type_getsets[] = {
 	{"__name__", (getter)type_name, (setter)type_set_name, NULL},
 	{"__bases__", (getter)type_get_bases, (setter)type_set_bases, NULL},
@@ -580,6 +629,8 @@
 	 (setter)type_set_abstractmethods, NULL},
 	{"__dict__",  (getter)type_dict,  NULL, NULL},
 	{"__doc__", (getter)type_get_doc, NULL, NULL},
+	{"__instancecheck__", (getter)type_get_instancecheck, NULL, NULL},
+	{"__subclasscheck__", (getter)type_get_subclasscheck, NULL, NULL},
 	{0}
 };