I have a pair of Yoshayaki (Yoshiaki?) shears, bought about 3 years ago.. Up until about 2 months ago I would have reported as a satisfied customer, but the same exact thing you described above happened to mine... I don't think the branch I was cutting was huge/ way too big for the tool or anything like that, but the tips do not cross any longer, it doesn't meet flush and won't cut all the way to the tip... Basically they are trashed. I bought a Kaneshin shear straight from the factory to replace them and could not be happier... All the Kaneshin tools I have purchased are excellent. I have owned some cheap Chinese junk tools, medium quality Japanese tools and now have a few very good tools- Kaneshin and Kiku are the high quality ones I now own and both are fantastic tools! Sharp as Hell, solid, well built, blades meet the way they should, cuts are smoother... The difference is bigger than I anticipated. I started a thread some time ago about Kiku (well made Japanese tools) vs Kiku Classic (cheaper Chines made alternatives..). I own a concave cutter of each and don't even use the classic any longer.
I am slowly replacing my tools with better ones as the old ones rust, break or just wear out. No need to drop $1400 on a whole set all at once. Buy the tool you use most first, buy a good one and as you figure out which others are most important buy them along and along as you go. Before you know it you will have a nice assembly of tools and doing it progressively lets you adapt to your needs as you skills grow.
Price wise- Yoshayaki are good for the money, but KANESHIN is WAYYYYY better and though they cost about double/ Triple what Yoshayaki costs, Kaneshin is still about half what Masakuni will run you (or maybe 1/10th the cost if you are buying the hand made "special" Masakuni stuff!) Kiku is probably between Masakuni and Kaneshin in price but still affordable.. And it seems you can find them on sale for really good prices sometimes if you look around a bit. I got a SOLID pair of concave cutters for like $50 at the Carolina Expo last year... I think it was Meco Bonsai that I bought them from maybe...?
