There are no records indicating that cultivation of buckwheat which was referred to as 'sobamugi' (buckwheat) ("Honzowamyo" (dictionary of medical plants) and "Wamyoruiju-sho" - Kango-Japanese Dictionary in mid Heian period) or Kuromugi (buckwheat) ("Wamyoruiju-sho") was active in those days (and, additionally, buckwheat was defined as a type of wheat in "Wamyoruiju-sho").
当時「曾波牟岐（蕎麦/そばむぎ）」（『本草和名』・『和名類聚抄』）あるいは「久呂無木（くろむぎ）」（『和名類聚抄』）と呼ばれていたソバが積極的に栽培されたとする記録は見られない（なお、『和名類聚抄』では、蕎麦（そばむぎ）をムギの1種として紹介している）。