Yes. That.
(a) isn't worth bothering with. VERY limited, only 48 chords and no provision for on-bass.
(b) is called "Multifinger." But not all multifinger are created equal. The implementation on the YPG-535 works pretty well, and is actually BETTER than the one on the Genos and SX. Why!? Try it and see for yourself.
Unfortunately neither of these are compatible with the the Korg-Roland-Ketron-GEM approach. If you play C and Bb expecting C7 you're gonna be disappointed because you'll get C minor! The fingering is so different, you might as well play a clarinet!

So I knuckled down and tried to learn the "AI Fingered" system that everyone on PSRTutorial brags about. It's pretty logical with a few quirks, and it is helpful if a song has a lot of slash chords. BUT-- the burn is, a single note is recognized as a UNISON. What?!? I mean, how often do you use that? Someone should make Steve Deming write on the blackboard 100x "One finger equals a major chord!" Seriously, Yamaha should allow the user to choose whether a single key is silent (two notes minimum), major chord, or unison for those who like it the way it is now.

I mostly play simplified scores. They have a lot of major, minor, 7th chords with the occasional slash chord thrown in. Being able to play a major chord with one key facilitates fast transitions and often saves me the need to reposition my whole hand. By contrast, Roland's Chord Intelligence allows one-finger majors, two-finger minors, 7ths, Maj 7ths, and Dims in pretty much any inversion. All of the trigger notes are part of the chord. When you activate Bass Inversion, it will also permit playing many slash chords with just two notes. It doesn't penalize you for playing all the notes, and it will accurately recognize 9ths, 13ths, etc. if you are skilled enough to play them. I've found that I can play more music accurately and easily with the Roland system, compared to any other.

To make songs with occasional slash chords easier, I figured out a way to use the Midi Solutions footswitch controller to make Bass Inversion a MOMENTARY function. (This should have been an option from the factory!) When I press and hold the pedal, the lowest key controls the bass. As soon as I release the pedal, it plays the root bass for any inversion. The factory requires one push to turn it on, and another to turn it off. That's hard to do if the chords change on every quarter note.

Korg's Fingered 1 is similar to Roland's approach. If you don't play any slash chords it might be better. But Korg tried to give the player a shortcut for everything, and sometimes it gets in the way. For example, if you play G-C expecting C/G you get Gsus4. If you really want C/G you have to stretch for the 3rd above. If you want C/E you had better get that G in the middle down, otherwise you get Eaug. I rarely encounter augmented chords, so this logic is frustrating.

If Roland abandons the arranger market, I hope they license their Chord Intelligence to a third party, or even release it into the public domain. It's been around practically unchanged since 1996, and it's truly ingenious! I'm done with Yamaha for real-time play unless they swallow their stubborn pride and make the changes I describe. But all brands would benefit from more customizability in this important facet of arranger operation.

Yup. What HE said!

Well said, TedS.

Dave...Do still have Yamaha P-121 Piano?...If So is the Grand Piano Sounds close with the 900x...Decay and sustain, etc...Thanks Harold

I do, Harold. I haven't noticed that same symptom on the P-121, that's what makes me think it's a triggering issue. I need to research this more.

Hi Dave,
if you come up with a better setting for piano on sx luv to know what it is. I just press the sustain button on mine for r/h melody, good enough for my playing skills .
Weird , I don’t like using the sustain pedal on the keyboard, but no hassle using it on the p121.

I did manage to hook up my p121 to sx900 via via USB cables using my laptop as an interface. Not ideal but just wanted to see how sx piano sounded played via the weighted keys. Gives a much nicer feel.

Still debating whether I just keep using them as 2 seperate instruments or go out and purchase a proper interface.

Rikki, I just bought this from Amazon: https://smile.amazon.com/gp/product/B01CFOHF9M/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
Hoping it'll make life a little simpler, and declutter a few wires in my living room, where the 121 lives. If I tweak the SX piano, I'll share the results! I was thinking of you last night - a guitar player sat in who was from Australia! He was born here, but lived down under for most of his life, and now he's back. Found us on www.openmics.org - a service that brings many musicians through our doors.

Hi Dave,
actually have one of those, they included it in my p121/sx900 package.
To be quite honest , I haven’t really played around with it too much.
I tried it with the p121 and the piano app, when I first bought it, but I must have been doing something wrong, I couldn’t get them to connect. I eventually got the camera adapter , to work , so didn’t want to start messing around with it.

Never really used Bluetooth for anything except for the phone connection to hubby’s car.
That was a nightmare too, had to take it back to BMW, to get his $12 flip phone ( which did actually have Bluetooth) connected to his $80k BMW. Should have have seen the lady technicians face, priceless, when she asked him why he didn’t get a decent phone. His answer was, oh, I could have spent $18 for the upmarket version, but I did want to spend the extra. Haha.

Thank goodness the kids bought him an iPhone for his 70th birthday, he wouldn’t let me do it.

Couldn’t get that open mics link to work, so looked it up on google.
Interesting.