what is the {start time} for {Toshiba} has {chief executive officer} as {Nobuaki Kurumatani} ?
When did Nobuaki Kurumatani become CEO of Toshibo?
When did Nobuaki Kurumatani become  chief executive officer at Toshiba?
SELECT ?x WHERE { ?g property:start_time ?x . resource:Toshiba property:chief_executive_officer ?g . ?g property:chief_executive_officer resource:Nobuaki_Kurumatani }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q49125> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P169> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q11637325> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q49125 p:P169 ?s . ?s ps:P169 wd:Q11637325 . ?s pq:P580 ?value}