query: #title: items for Emperors of Japan would have this property
  # Complex constraint from [[Property talk:P6902]]
  #
  SELECT ?item ?d
  {
  	?item wdt:P39 wd:Q208233 . 
      MINUS { ?item wdt:P6902 [] } 
      OPTIONAL { ?item wdt:P570 ?d  }
  }
  ORDER BY DESC(?d) 
  LIMIT 50