Question: when did the first samurai exist in japan
[{'answer': '702 AD', 'provenance': [{'wikipedia_id': '28288', 'title': 'Samurai', 'start_paragraph_id': 5, 'start_character': 433, 'end_paragraph_id': 5, 'end_character': 439, 'bleu_score': 1.0, 'section': 'Section::::History.:Asuka and Nara periods.\n'}]}, {'provenance': [{'wikipedia_id': '28288', 'title': 'Samurai', 'start_paragraph_id': 5, 'start_character': 0, 'end_paragraph_id': 5, 'end_character': 1052, 'bleu_score': 0.6685146153021271, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5178756599613619980}, 'section': 'Section::::History.:Asuka and Nara periods.\n'}]}]