Koetsu cartridges - what arms work?

So far the best tonearm (especially, but not only for Koetsu)
is the ViV Rigid Float.

In my system this beast has beaten all conventional tonearms
so far including classic 12", DaVinci, Graham, Reed and others.

idl57, It's not surprising that the Koetsu tonearm did not float your boat. Upon close inspection of photos, it appears to be a Jelco tonearm in Koetsu guise, which of course raises its cost by a factor of 2 or 3 compared to a Jelco 750.  Not that Jelco tonearms are "bad" per se.  

racedoc,  Can you say more about the Viv?  I was in Tokyo a year ago and lingered in Yodibashi Camera in Akihabara for more than an hour deciding whether or not to buy a Viv.  They had all 3 sizes on display (7, 9, and 14-inch)  Which do you have? I calculated that tracking error goes down significantly when you go from 7 to 9 but from there going to 14 doesn't help enough to warrant the extra length, possible issues with resonance, and the difficulty in mounting.  I would have bought the 9-inch, had I gone ahead with purchase.  My interest in the Viv is based on my own home experience with one of the only other "underhung" tonearms on the market, the RS Labs RS-A1.  That tonearm is also more excellent than one would want to believe it is by just looking at it.  This led me to believe that underhang is a serious alternative, that tracking angle error is not such a big deal (because both underhung tonearms develop a lot of tracking angle error as they traverse the LP surface, more than with any overhung tonearm).  By inference, this also suggests that headshell offset angle IS detrimental to maximum fidelity. (For others, the headshell on an underhung tonearm is not offset at an angle to the arm wand.)

Hi lewm,

I have the 9"-version in my system. Due to the underhang the 
"mounting distance" is with 273mm quite long and it looks not
really short.

Fascinating is that some friends and me have played around
with a huge variety of different cartridges (weight, quality and
compliance) and there was not one cartridge playing not better
than in other high end tonearms.
(Ortofon 2M, Ortofon Vero, Ortofon Cadenza Black, Ortofon SPU,
ZYX 4D Atmos, DS Audio DS-W1, DS Audio DS-002, Koetsu
Rosewood and others).

The arm has no antiskating function. But this is not necessary,
because the maximum skating force is exactly so strong than
with a conventional arm and perfect antiskating adjusted.
(According to the advice of Mr. Lederman)

I recently tried a Koetsu Jade with my Clearaudio Universal 12", and I’d say that arm is a no-go for Koetsu. Dynamically flat, a bit dead, definitely lacking the passion associated with Koetsu. However the Universal does very well with a Shelter Harmony; better than even the Graham for that cart.

The Graham Supreme and Fidelity Research FR64fx are far better matches for Koetsu. I also had an opportunity, several years ago, to purchase a mint Koetsu SA-1100 tonearm locally. After inspecting it in person, I passed -- the build quality and feel of my FR64fx far exceeds the SA1100 in every way. It was obvious to me, even then, that the Koetsu arm was a Jelco build. Cool head-shell though!!

Urushi here (original Sugano Sr.) and the SME V seems made for it.