what is the {start time} for {Empire of Japan} has {shares border with} as {Republic of China (1912–1949)} ?
What year did Japan begin to share a border with China?
SELECT ?value WHERE { wd:Q188712 p:P47 ?s . ?s ps:P47 wd:Q13426199 . ?s pq:P580 ?value}
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q188712> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P47> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q13426199> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

When did China and Japan become border countries?