diff --git a/src/diana/sgfParser/property.py b/src/diana/sgfParser/property.py
--- a/src/diana/sgfParser/property.py
+++ b/src/diana/sgfParser/property.py
@@ -1,4 +1,5 @@
 import re
+from datetime import date
 import logging as log
 
 from .propValues import choose, singleton, listOf, compose, number, real, double, color, text, empty, anything, point, move, stone
@@ -8,6 +9,10 @@ GAME_INFO=1
 UNKNOWN=99
 
 
+class DateException(Exception):
+	pass
+
+
 class Property:
 	identRegexp=re.compile(r"[A-Z]+")
 
@@ -32,6 +37,8 @@ class Property:
 			i,x=choose(listOf(anything), singleton(anything))(s,i)
 			res.name="_"+res.name
 		res.value=x
+		if res.name=="DT":
+			res=DateProperty(x)
 		i=skipWhitespace(s,i)
 		return (i,res)
 
@@ -46,8 +53,7 @@ class Property:
 		if name in Property.patterns:
 			return Property.patterns[name](s,start)
 		else:
-			# !! raise or log or ignore
-			# print('warning, unknown property "{0}" at position {1}'.format(name,start))
+			log.info("unknown property %s at position %d",name,start)
 			return choose(listOf(anything), singleton(anything))(s,start)
 
 	@property
@@ -63,8 +69,9 @@ class Property:
 		return res
 
 	def __str__(self):
+		name=self.name.lstrip("_")
 		val="[{0}]".format(self.value) if not isinstance(self.value,list) else "".join("[{0}]".format(x) for x in self.value)
-		return "{0}{1}".format(self.name,val)
+		return "{0}{1}".format(name,val)
 
 	patterns={
 		"B":singleton(move),
@@ -139,4 +146,42 @@ class Property:
 	}
 
 
-# !! TODO: date
+class DateProperty(Property):
+	def __init__(self,value):
+		super().__init__()
+		self.name="DT"
+		self.value=[]
+		self.rawValue=value
+		self.parse(value)
+
+	def parse(self,s):
+		regexp=re.compile(r"\d{4}(-\d\d){0,2}(,(\d{4}(-\d\d){0,2}|\d\d(-\d\d)?))*")
+		match=re.search(regexp,s)
+		if not match:
+			raise DateException('Could not parse a DT value: "{0}"'.format(s))
+		substr=match.group(0)
+		dateStrs=substr.split(",")
+		dates=[]
+		prevFormat=None
+
+		for s in dateStrs:
+			try:
+				(prevFormat,d)=DateProperty.parseSingle(s,prevFormat,dates[-1] if dates else None)
+			except ValueError:
+				raise DateException('Could not parse a DT value: "{0}"'.format(s))
+			dates.append(d)
+		self.value=dates
+
+	@staticmethod
+	def parseSingle(dateStr,prevFormat,prev=None):
+		tokens=dateStr.split("-")
+		num_tokens=list(map(int,tokens))
+		if len(tokens)==3:
+			return ("YMD",date(*num_tokens))
+		elif len(tokens)==2:
+			if len(tokens[0])==4: return ("YM",date(*num_tokens,1))
+			else: return ("MD",date(prev.year,*num_tokens))
+		else:
+			if len(tokens[0])==4: return ("Y",date(*num_tokens,1,1))
+			elif prevFormat in ("YM","M"): return ("M",date(prev.year,*num_tokens,1))
+			else: return ("D",date(prev.year,prev.month,*num_tokens))