Hey so I'm looking to use Japanese bond rates for the 3-month, 5-year, and 10 year government bonds going back 20 years or so. Unfortunately I'm presenting this in a context where I have to use free (mostly government) data sources, so Bloomberg or CapIQ are out. I've found stuff for the 10 year rate but I'm totally stuck on the 5 year and 3-month rate going further back than a few months any suggestions?
Thanks!