There was a variation called 'choko ton,' tonkatsu with a chocolate bar inside and another called 'matsumoto don,' a variety of katsudon, in which onion slices were replaced with shredded burdock and yam.
板チョコを中に入れた「チョコとん」、カツ丼のタマネギをゴボウと山芋の千切りに替えた｢松本丼｣