I have to use a cleaver they are very hard. I just quarter one, clean out all the seeds with a spoon, cover each chunk with foil, not too tight, and put on a cookie sheet. Bake at 350 for an hour or until poked with a sharp knife to be sure they are soft but not mushy. Then I let them cool, use a peeler knife to cut off the rind and freeze in a foodsaver bag, one bag with enough for one pot of soup. Usually cut the cooled pieces into smaller chunks. So easy to make a pot of the soup this way. Plus I had a lot of squash this year.
Thanks. I once actually peeled one by hand and chopped it up with a big knife.
Later, I thought a cleaver and mallet would do a good job ;-)