Years ago he wrote to the Victoria and Albert museum and sent them some faxes of the signature of the bottom one they said it may be made by Bishu YOSHIMITSU of Bizen province,(modern day Okayama).Number of smiths using this signature,earliest dates,Dated 1350-1688 -but all seemed to sign using a longer signature with honorific titles.
The curator goes on to say the blade above the habaki hamon resembles the sloping style of the Yokoyama school.
Not that that means much to me! at this stage.
Rohan.