I went out onto the WWW to get some comparative photos to try to get some better comparitve charactoristics. Most of these were from the Smithsonian and two are credited in the picture name. I appears tha Bell 47 B (MASH version) is what's in the picture
1. Bell 47 B, first production version before militarization...didn't do so well in production
2. Bell 47 B / H-13 military version courtesy of Spectre63, note wheels on landing gear
3. Bell 47 J / H-13 President Eisenhower's Helicopter, the First "Helicopter 1" (note wheels, or lack of on landing gear)
4. Sikorsky XR-4 Same time period, similar size note landing gear wheels
5. Sikorsky XR-5 Same time period, similar size note landing gear wheels
6. Bell 47J Ranger, note landing gear, with wheels
opps, pictures didn't come out as numbered, so left to right, top down: Bell 47 B Civilian; Bell 47 B Military; Bell 47 J Presidential; Sikorsky XR-4, Sikorsky XR-5 and Bell 47 J ranger
Judging from all these, the Bell 47 B (H-13) is what's pictured. I don't think any J's were in Japan during the 1953 time period.