Recognizing the types currently in service were getting along in the tooth, the Imperial Japanese Navy placed an order with Nakajima for an advanced torpedo bomber. The Model 14 Carrier-based Attack Aircraft was required to have a top speed of 250 kts or better, a cruising range of 1800 NM, and be powered by a 1500hp engine. Nakajima convinced the authorities that these specs would require the NK7A Mamoru ("Guardian") engine, then in development, rather than Mitsubishi's Kasei ("Mars") which the IJN had suggested. This was to be the aircraft's downfall.

Development was long and plagued with difficulties. Aside from the challenge of just meeting the specifications, Nakajima designers were kept busy with problem after problem. Excessive weight required Fowler flaps to be installed and landing gear strengthened. Serious directional stability problems and the unfortunate tendency to ground loop on take-off and landing, revealed during initial flight tests, required more modifications. Most troublesome was the just finished Mamoru engine. These problems delayed the type's adoption into service until August 1943. It wasn't until the Battle of Bougainville in November 1943 that the B6N1 "Tenzan" (Mountain of the Sky" ) entered combat, where it was known to the Allies as "Jill".

Continuing problems with the engine led to the redesigned Tenzan Type 12. The Mamoru was dropped in favor of the more reliable, but less powerful, Kasei. Other changes included a slightly smaller propeller diameter, slightly lengthened fuselage, increased defensive armament, and changing the tailwheel from retractable to fixed. This revised model, the BSN2 depicted in the kit, entered service in March 1944. Other revisions, to be incorporated in a B6N3 model, were planned but never produced.

Approximately 1270 B6N aircraft in all variations were built before the war ended, including 133 B6N1 models. While fast and formidable, the type never fully lived up to IJN expectations. Jills served extensively in the last year of the war and many were expended in kamikaze attacks.

Wow.

I've said it before and I'll say it again - we are living in the Golden Age of aviation scale modeling. This kit is all the proof you need.

Upon opening the box, you are greeted by two clear bags containing 11 sprues - 10 in the usual grey, one clear - as well as three sets of poly caps (two clear-ish, one black). This thing has more parts than a chicken processing plant! Panel lines are finely engraved as we've come to expect. Molded-in detail is the best I've ever seen on a Hasegawa kit - they just keep getting better, release after release.

The cockpit assembly mimics the latest resin sets, with separate sidewalls enclosing the tub. Two separate decals are provided for the instrument panel - one with dials on black carrier and one with dials on clear carrier. Options are provided for the ventral defensive MG (similar to the tunnel gun in an Avenger) and as well as two stowed rear-facing upper guns. The MGs themselves are nice, but I'll probably replace the ring sites with photoetch from the spares tray. Stacks of spare ammo drums are molded into the fuselage and sidewalls. They are unrealistically deep - but you won't see that when the cockpit is in place. You'll only see the nicely done tops. Radio direction-finding equipment was carried by about a third of operational Jills, and Hasegawa has included a loop antenna to depict that option.

The rest of the model is equally well detailed. The one-piece engine is represented by cylinder fronts, showing two banks of 7 cylinders. Once enclosed by the tight fitting cowl they'll look right nice. The landing gear is also crisply molded, lacking only brake lines. The wheels are two piece and flattened (though not bulged), which I guess is acceptable, as the only picture I've seen with this beast on the ground shows the wheels noticeably flat. Wing fold detail is nicely done as well. That's right - Hasegawa has given us the option to fold the wings! Separate inserts are provided for wing halves, along with hinges and supports - and stays for securing the outboard sections to the fuselage. Diagrams are also provided showing how to position the wings. I'm not sure how much this was used - most Jills operated from land bases after the carriers were all sunk - but it's a nice option.

Rounding out the kit is a sheet of crisp, in-register decals. In addition to markings for two aircraft (256th Attack Squadron/752d Naval Flying Group "White 33" and a machine from the 210th Naval Flying Group) a slew of yellow and red numbers are provided, presumably for serials of other machines. A separate white "33" is supplied for those (like me) who will choose not to use the kit's hinomarus.

Instructions are the typical Hasegawa exploded diagrams, with paint call outs marked with reference to Gunze and Mr. Color paints. You'll want to pay close attention to the sheet - there are a number of spots where you'll have to drill out flashed over holes to attach various options.

Summary