Small bowel distension with no fluid content in ascending colon (black arrowheads: Fig.5-Fig.8) indicates high possibility of mechanical obstruction. Two findings of massive ascites (reference mark in Fig.1 and Fig.2) and gasless distended small bowels are suggestive of strangulated obstruction. Satisfactory contrast-enhancement of wall of distended small bowel and absence of mesenteric stranding are suggestive of simple obstruction. In order to clarify this challenging problem, distended small bowel should be tracked down starting from Fig. 20. A gets to obstruction point P in Fig. 9 which connects to collapsed small bowel (SB). Though 1 advanced to 13 of Fig.7 and further tracing is impossible, absence of another obstruction site in the vicinity of P of Fig.9 indicates little possibility of strangulated obstruction and leads to diagnosis of simple obstruction. Because abdominal pain aggravated in spite of ileus tube insertion, an operation was undertaken on the second day. Ileum at 45cm from cecum adhered to transverse mesocolon resulting in kinking and simple obstruction, and adhesiotomy was performed. In difficult case like this for accurate diagnosis, CT scan after gastrografin injection through NG tube or ileus tube is extremely useful (Expert course EE16, EE27) and should be considered as next step.