I have heard(read) two Japanese ladies said " no such thing as Rice paper. One is Japanese calligrapher who demonstrated calligraphy at Peobody Essex museum recently and other is Bimonthly Japanese Gardening publisher wrote few years ago.
It is such things rice paper. To check it, Just use Kokugo Jiten to reffer word of Wara hanshi.
Washi is high grade paper made from Mitsumata,and kozo which are med size shurb growing in Japan.
Rice paper made from rice strow or wheat straw. we call it" wara hanshi ", wara means rice or wheat straw
hanshi means half size. when I practiced calligphy many years ago( 50 years or more), at School and temple, we used wara hanshi because it was cheap to produceit.
To speak at public, information must be accurate. Shame on them.
You can laugh my misspeliings and bad grammer ;D
Most calligraphers today use a form of mulberry paper for shodou.
Mullberry grow rapidly and cheaper to produce than Kozo or mitistumata. My decesed father inlaw who was calligrapher had Kino Turayuki's calligrahpy which is about 1000 years old was made of Kozo or Mitustumata washi. A Papar made in China, don't call washi, no matter what material is. :D ( strictly speaking)
Mitusmata has cream color flower which has delicate sweet fragrance, bloom early spring, probably you can find at nusery . yama