In the Japanese case the application of these principles was not so easy. In selecting the nearest undefended point for a landing, it was not only batteries, or even the army in Port Arthur, or the troops dispersed in the Liaotung Peninsula that had to be considered, but rather, as must always be the case in the future, mines and mobile torpedo defence. The point they chose was the nearest practicable bay that was unmined. It was not strictly out of mobile defence range, but it so happened that it lay behind islands which lent themselves to the creation of fixed defences, and thus it fulfilled all the recognised conditions. But in so far as the defences could be turned by the Russian fleet a covering squadron was necessary, and the difficulty of choosing a position for it was complicated by the fact that the objective of the combined operations was not merely Port Arthur itself, but also the squadron it contained. It was necessary, therefore, not only to hold off that squadron, but to prevent its escape. This indicated a close blockade. But for close blockade a position out of night torpedo range is necessary, and the nearest point where such a position could be secured was behind the defences that covered the disembarkation. Consequently, in spite of what the strategical conditions dictated, the covering squadron was more or less continuously forced back upon the army and its supporting force, even when the support of the battle-squadron was no longer required. In the conditions that existed nothing was lost. For the lines of the Japanese fixed defences were so near to the enemy's base, that by mining the entrance of the port Admiral Togo ensured that the enemy's exit would be slow enough for him to be certain of getting contact from his defended anchorage before the Russians could get far to sea. What would happen in a case when no such position could be secured is another matter. The landing place and supply base of the army must be secured against torpedo attack, and the principle of concentration of effort would suggest that the means of defence should not be attenuated by providing the covering squadron with a defended anchorage elsewhere. Thus it would appear that unless the geographical conditions permit the covering squadron to use one of its own national bases, the drift of recent developments will be to force it back on the army, and thus tend to confuse its duties with those of the transport squadron. Hence the increased importance of keeping clear the difference in function between the two squadrons.