   func updateRotation(_ radian: Double) {
     
     let currentDeg = radiansToDegrees(radian)
-    let variation = getVariation(prevDeg, current: currentDeg)
+    let variation = getVariation(currentDeg)
     
     arrow.transform = CGAffineTransform(rotationAngle: CGFloat(radian))
     

  }
  
  // 引数で与えた角度の中に含まれるスリットのindexを配列にして返す
  fileprivate func slitIndexInRange(_ prev: Double, current: Double) -> Array<Int> {
    if prev == current {
      return []
    }
    
    let _prev = restrict(prev)
    let _current = restrict(current)
    let _min = min(_prev, _current)
    let _max = max(_prev, _current)

    switch playerType {
    case PlayerType.OneShot:
      // OneShot
      let passed_slit = slitIndexInRange(currentDeg)
      
      if 0 < passed_slit.count {
        
