Gastric peristalsis and pyloric movement were observed by the gastric fibrescope GTF in 54 subjects either with normal gastric mucosa or mild to moderate atrophic gastritis. In a few instances, simultane-ous serial radiographs were also taken for comparison. The activity of gastric peristalsis was classified into the following 5 grades and their relation to pyloric movement was studied: Grade I Absence of peristalsis A. With patulous pylorus seen as a dark round hole; most common. B. With completely closed pylorus seen as a pinpoint; infrequent. C. With slight pyloric movement; extremely rare. Strong asterisklike contraction is never seen. Grade. II Mild peristalsis A. A round peristaltic wave is formed in the antrum, advancing slowly toward and disappearing immediately proximal to the pylorus (Fig.1-A). B. A non-propulsive contractile ring occurs and disappears repeatedly immediately proximal to the pylorus (Fig. 1-B). Grade III Moderate peristalsis Peristaltic wave is formed in the proximal antrum and advances distally, when the pylorus is open (Fig. 2-a); when the wave reaches the segment immedi-ately proximal to the pylorus, the pylorus starts closing, peristaltic wave contracts strongly to form a ring with radiating folds in the pyloric region (Fig. 2-b). The ring becomes more constrictive, and reaches the pylorus(Fig. 2-c). A complex, asterisklike contraction involving the pylorus is then formed and protrudes (Fig.2-d). Constriction dissolves from the centre enabling a glimpse of the closed pylorus (Fig. 2-e, f), followed by opening of the pylorus (Fig. 2-g) Grade IV Vigorous peristalsis The peristaltic wave is more marked and deeper, and moves with stronger antral constriction. The proximal side is elevated and longitudinal folds are seen over the surface of the wave (Fig. 3-a). With its distal movement luminal constriction and longit-udinal folds become more marked, to completely occlude the lumen (Fig. 3-b). When the peristaltic movement is vigorous, this constriction occurs con-siderably proximal to the pylorus, and the more active the peristalsis, the more proximally the constriction starts. The contraction ring protrudes proximally and the mucosa swells up through its centre and seemingly migrates centrif ugally (Fig. 3-c). Occasionally, duodenal juice regurgitates through it. The constriction dissolves gradually and the closed pylorus becomes visible through its opening (Fig. 3-d). The peripyloric area then becomes flattened usually with a shallow contraction ring remaining(Fig.3-e). Grade VV Markedly vigorous peristalsis The peristaltic wave is more prominent and stron-gly constricts the lumen already near the pars angularis with strong contraction of the entire antrum, but this type is extremely rare. Radiologically, when the peristaltic wave reaches, the proximal loop of circular muscle, a special muscular structure of the antrum, the onward movement is aborted, and the circular muscle loop contracts accompanying shortening of the lesser curve, followed by contractile movemnet of the whole prepyloric segment, a gastric emptying movement called "antral systol". The luminal constriction resembling the pylorus, as mentioned in Grade IV peristalsis, was considered by Schindler to be the pylorus itself or its vicinity, but, as it occurs considerably proximal to the pylorus, it cannot be the pylorus itself. While Fukuchi regarded it as representing the antral systol, , the swelling up of the mucosa through the constri-ction suggests a constant onward movement of peri-staltic wave, and may require an explanation diffe-rent from the so-called antral systol. The pyloric movement was usually associated with gastric peristalsis; in the absence of peristalsis or in the case of weak peristalsis, the pylorus was usually patulous. Occasionally, however, pyloric movement, though mild, was observed independent of peristalsis, suggesting some autonomy under certain circumstances. The peristalti