Rare historical term for an order issued by the Imperial Japanese Navy. Compare with 大海指 (たいかいし), which may refer to a similar or related concept.
See also: 大海指
The 大海訓 was a type of order used in the former Imperial Japanese Navy.
Compound of 大海 (たいかい, 'great sea' or 'ocean', here likely referring to the navy) and 訓 (くん, 'instruction' or 'precept'). The exact historical derivation is uncertain; the term appears to be a specialized Imperial Japanese Navy term.