RS1500 or some later 59 inch Yanmar tiller, is likely the original matched tiller for YM2310.
However ... the Yanmar rice paddy tillers don't take such an aggressive bite compared to an American tiller.
Compare the tines. The Yanmar design mostly slices downward vertically then has a curled tip, while the American tines have broad flat blades parallel to the earth. I suspect that design absorbs more horsepower.
I would rent a 5 ft tiller for one time use, and take several passes at increasing depth. But only after appraising how well that worked would I buy an American-design tiller. I think you might conclude a smaller tiller is a better match. Or a Yanmar tiller if you can find one.
One other consideration is multiple passes with a tiller may pulverize the soil to fine powder. That's not good. You want chunks that water can settle down into, not flour-consistency that will turn to impermeable adobe next time it gets wet.
Making a first pass with box blade rippers would break up roots and thatch, and make the tiller's job easier.
