@@ -102,7 +102,7 @@ Using json.tool from the shell to validate and pretty-print::
         "json": "obj"
     }
     $ echo '{1.2:3.4}' | python -mjson.tool
-    Expecting property name enclosed in double quotes: line 1 column 1 (char 1)
+    Expecting property name enclosed in double quotes: line 1 column 2 (char 1)
 
 .. highlight:: python3
 
 
@@ -97,7 +97,7 @@
         "json": "obj"
     }
     $ echo '{ 1.2:3.4}' | python -m json.tool
-    Expecting property name enclosed in double quotes: line 1 column 2 (char 2)
+    Expecting property name enclosed in double quotes: line 1 column 3 (char 2)
 """
 __version__ = '2.0.9'
 __all__ = [
 
@@ -32,7 +32,7 @@ def linecol(doc, pos):
         newline = '\n'
     lineno = doc.count(newline, 0, pos) + 1
     if lineno == 1:
-        colno = pos
+        colno = pos + 1
     else:
         colno = pos - doc.rindex(newline, 0, pos)
     return lineno, colno
 
@@ -7,7 +7,7 @@
         "json": "obj"
     }
     $ echo '{ 1.2:3.4}' | python -m json.tool
-    Expecting property name enclosed in double quotes: line 1 column 2 (char 2)
+    Expecting property name enclosed in double quotes: line 1 column 3 (char 2)
 
 """
 import sys
 
@@ -181,6 +181,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #17225: JSON decoder now counts columns in the first line starting
+  with 1, as in other lines.
+
 - Issue #13700: Fix byte/string handling in imaplib authentication when an
   authobject is specified.
Original file line number	Diff line number	Diff line change
@@ -102,7 +102,7 @@ Using json.tool from the shell to validate and pretty-print::
102	102	"json": "obj"
103	103	}
104	104	$ echo '{1.2:3.4}' \| python -mjson.tool
105		- Expecting property name enclosed in double quotes: line 1 column 1 (char 1)
	105	+ Expecting property name enclosed in double quotes: line 1 column 2 (char 1)
106	106
107	107	.. highlight:: python3
108	108
Original file line number	Diff line number	Diff line change
@@ -97,7 +97,7 @@
97	97	"json": "obj"
98	98	}
99	99	$ echo '{ 1.2:3.4}' \| python -m json.tool
100		- Expecting property name enclosed in double quotes: line 1 column 2 (char 2)
	100	+ Expecting property name enclosed in double quotes: line 1 column 3 (char 2)
101	101	"""
102	102	__version__ = '2.0.9'
103	103	__all__ = [
Original file line number	Diff line number	Diff line change
@@ -7,7 +7,7 @@
7	7	"json": "obj"
8	8	}
9	9	$ echo '{ 1.2:3.4}' \| python -m json.tool
10		- Expecting property name enclosed in double quotes: line 1 column 2 (char 2)
	10	+ Expecting property name enclosed in double quotes: line 1 column 3 (char 2)
11	11
12	12	"""
13	13	import sys