A note on numbers and nomenclature

Military organisations run on numbers, and thus the reader continuously encounters unit numbers in Darwin Spitfires. As an aid to memory, RAF/RAAF units are indicated by cardinal numbers, e.g. ‘2 Squadron’, while US units are indicated by ordinal numbers, e.g. ‘380th Bomb Group’, as per national practice. Furthermore, as a memory aid to help the reader distinguish between the three Spitfire squadrons, the sole British unit has a two-digit number - 54 - while the two Australian units have three-digit numbers, e.g. 452 (pronounced ‘four fifty two’).

While dedicated aviation enthusiasts are comfortable with transliterated Japanese terms like Kokutai, Sentai, Chutai, and Koku Sentai, the general reader is not, so I have used militarily-logical English-language equivalents, such as ‘Air Group’, ‘Squadron’, or ‘Air Division’. This also helps to demystify the enemy.

Japanese aircraft nomenclature of the time was very confusing and unsatisfactory, with three different systems operating simultaneously. During the war, allied air forces avoided the inevitable confusion by using made-up reporting nicknames. Thus the names ‘Zeke’, ‘Hap’, ‘Betty’, and ‘Dinah’ were applied to the four Japanese aircraft types most often encountered over Darwin. However, perpetuating this allied-invented system is unsatisfactory, eliding as it does the true aircraft designations.

However, the primary Japanese year-number system of nomenclature, such as ‘Type 1’ land-based navy bomber or ‘Type 0’ carrier fighter, is also unsatisfactory and confusing, due to duplication across different aircraft categories (e.g. Type 0 navy fighter and Type 0 army reconnaissance plane). I have therefore used the Ki-numbers for army aircraft, thus ‘Ki.49’, and the US Navy-style alpha numerical system for navy aircraft, thus ‘G4M’. Even this is tedious and potentially confusing, so wherever possible I have used the names given to these aircraft types by their user services, thus ‘Zero’ navy fighters and ‘Hayabusa’ army fighters.

The famous Zero fighter was referred to in the original 1 Fighter Wing sources as either the ‘Zeke’ or the ‘Hap’, referring to the Models 21/22 and Model 32 respectively. In the Darwin raiding context, the differences in performance between these sub-variants were minor, and indeed it was only their wingtip shape that distinguished them in the eyes of the Spitfire pilots. Moreover, the pilots’ aircraft recognition skills were such that army Ki.43 Hayabusas were identified as either ‘Haps’ or ‘Zekes’, while various types of Zero were sometimes identified as army Ki.43 and Ki.61 fighters, or even as navy B5N torpedo bombers. In short, if pilots made a distinction between a ‘Hap’ and a ‘Zeke’, then this might or might not have accorded with the facts of the case. Given this error and imprecision within the sources, all Zeros mentioned in the book, of whatever model, are referred to simply as ‘Zeros’ without differentiation.