The title of the module refers to the five Blades of Corusk, ancient magical swords which, according to the legends of Greyhawk's Suloise barbarians, can be brought together to be made even more powerful.
Not one of the great modules from TSR, but an interesting one. This is the first part of a trilogy, although the third part of the trilogy is a board game rather a module - the Greyhawk Wars game.
The early part of this adventure is quite good, there are some interesting and challenging encounters, some of which require combat, some of which can't be solved by combat. The final third of the adventure takes place inside a large orc city, and this is the part that doesn't work too well. Just because orcs have infravision (or darkvision as it would be these days) isn't a good reason for the entire city to be unlit. There are other things in the city that don't make sense. But, on the whole, the city can be made an interesting and challenging encounter with not too much work.
So, overall an adventure which plays an important part in Greyhawk history, but it's not one of the classic modules from the early period, like the Temple of Elemental Evil or the Giants series.