I think the Nissin Pocket Mini will prove to be the ultimate backpacking rod, especially for ultralight backpackers. The Pocket Mini 270 weighs exactly one ounce. It collapses to just 9 5/8". I don't think you will find a lighter, more compact rod anywhere (other than a true tanago rod). This is no tanago rod, though. It is a surprisingly capable keiru rod.
For backpackers who are not gram counters, I also have the rod in a 360 length, which weighs 1.7 ounce.
Nissin recommends tippet no stronger than 6.5X. If you don't have 6.5X use 7X tippet. If you get a snag at the extreme end of your cast (or a missed strike sends your fly to a treetop) and you cannot reach the line to break off the snag, pulling straight back on the rod could jam the sections if you use 6X or stronger tippet.
As you can imagine, with 15 or 20 sections in a package this thin, the section walls are quite thin and the tip itself is extremely thin. Collapsing this rod demands careful handling. Not to say it requires a surgeon's touch, but if you are ham fisted or if you would honestly describe yourself as hard on your equipment, this is not the rod for you. Being aware and being careful should be sufficient (but you do need to be careful).
Nissin Pocket Mini 360
Length Extended 11'10"
Length Collapsed 9 5/8"
Weight (with tip plug) 1.7 oz