A convoy exercise weighs neutral cargoes and fleet intervention

The exercise gave Japan low iron-ore stocks and a convoy of Japanese freighters accompanied by neutral Danish and Swedish oil cargoes. Its protection included six destroyers close to the convoy and a distant covering force of battlecruisers, a large carrier, and a destroyer flotilla. Britain hoped to defeat the covering force before the main Japanese battle fleet could arrive from Sasebo. The British battlecruisers had a four-knot speed advantage, but the scenario removed Ramillies and Royal Sovereign after a collision. Sailing times, the convoy's constraints, and the risk of leaving the advanced base exposed shaped the decision to attack. Carriers already formed a substantial part of this 1920s exercise. The criticism of the scenario is that Japan would more plausibly have assigned heavy cruisers to convoy cover than risked the Kongo-class battlecruisers.