Between February and March, the IJN Combined Fleet attempted to blockade Port Arthur by sinking older vessels at the entrance of the port, but this plan ended in failure (Port Arthur Blockade Operation).
連合艦隊は2月から5月にかけて、旅順港の出入り口に古い船舶を沈めて封鎖しようとしたが、失敗に終わった（旅順港閉塞作戦）。