It is definitely a blunder, I have had winning positions but could not find long mating nets (8+moves) and it turns out the mating sequence was the only right move.
Blundered by missing mate in 9!

This analysis is a bit arse about face I just played another game, this time I made a "mistake" as I missed mate in 10, yet on my op game I "blundered" as I missed mate in 9??

This analysis is a bit arse about face I just played another game, this time I made a "mistake" as I missed mate in 10, yet on my op game I "blundered" as I missed mate in 9??

I would first analyze the game by myself before I take it to a computer. Even then, taking it to a stronger player is more preferred then taking it to a computer, as humans make different types of moves, and often computers miss things that humans usually see and vice versa.
Jeremy Silman tells us to turn the computer off, (unless your a master) but we all gotta do what we gotta do. Have fun!
Hi, I just played a game and on a few occasions the game analysis says I blundered as I missed mate in 9 and on another move mate in 6. Wow that seems a bit harsh, I'm lucky if i can see 4-5 moves ahead. If you miss mate in 9 an inaccuracy or mistake perhaps but surely not a blunder.