I was looking at various katana and wakizashi yesterday and was confused by one particular wakizashi that was hira-zukuri(flat sided) on one face and shinogi-zukuri on the opposite face. I've not seen this before and initially thought it must have been 'over polished' and lost its shinogi line on the flat side. But it looks so purposeful and I wondered if the swordsmith used the blade as a kind of experiment, possibly because of overall dissatisfaction with the blade, or maybe it was an apprentice piece or...??