Split-Screen: "Tomonobu Itagaki and his former stalwarts at Team Ninja made 'breast physics' the norm in fighting games with their Dead or Alive series. Tecmo's Ninja Gaiden Sigma 2 continued that legacy, introducing a 'shaking' mechanic that would doubtless have allowed for some useful purpose when playing as the female shinobi. Namco-Bandai just recently enunciated on the physics governing their female cast in Soul Calibur IV."