I don't mean to sound trite, but I don't think this knife would be used against a tulwar or straight sword,....just against the wielder of the above!....
Re the cutting ability, In the book Sahib, there are numerous accounts of British soldiers being cut almost in two with these knives,...after the bearer of the knife had been 'run through'. so it would appear that adrenalin, and a sharp knife will work, even if it has a T shaped back!