I dissagree about not tempering, While one may not need very high temps, a stress buildup can break the blade, a bake at 350F won't remove much if any hardness, but it will remove much stress that builds up in the quench.
Having said that I know a few bladesmiths (Very few) that quench O1 in water, then do not temper at all, but if we were that good/lucky at this process we would not be posting questions like this in the first place.
And for a large blade such as a sword do we really want a RhC of 60+ anyway? play it safe and at least temper at 350F or so.
Another set of question for those that really recomend not tempering at all: Have you ever done it? more than once? have the baldes ever been used?
IMHO its asking for trouble not to releave the stresses induced by quenching in some way. But I admit that I am an arrogant bladesmith.