George S. Ledyard
My dojo-mates and I did played around after class with San-nin tanto/jutte dori jiyu waza (to non-japonophile: Three people mock knife / short stick free technique exercise)
All I can say is that in that circumstances, the only techniques that have any chance of successful application are still atemi-waza, kokyu-nage and plenty of tai-sabaki. Grappling is definitely a no-no.
Of all three I mentioned above, the tai-sabaki skill is the most important.
What about Aiki?