@therealturk: What are some examples you've seen that are unblockable but do not have the kanji? Because I don't think I've actually seen any to be honest.
Some of the bigger samurai dudes will smash you into the ground with their overhead jump attack if you are blocking. That one's got no kanji and while it can be parried, it can't be reliably blocked.
Then there is a samurai mini-boss in the castle that has an iaido attack that will cause you to take a ton of damage even if you are blocking. Again without a kanji, although it's at least pretty obvious he's winding up for something. I've also had that one do damage even if I parry it (which I know I'm doing because I'm damaging his posture) - but it is also two quick strikes, so it's possible I'm parrying one but not both.