In early 1942, the Japanese high command began planning operations in the New Guinea and the Solomon Islands, as part of an overall strategy of establishing bases in the South Pacific from which to interdict Allied lines of communication between the US and Australia.
As a part of this strategy, it was determined that there was a need to capture Lae, Salamaua, Tulagi and Port Moresby to establish bases, and to prepare for further operations in the South Pacific in order to push a defensive perimeter further south.
For the invasion of Salamaua and Lae, the Japanese 4th Fleet, under the command of Shigeyoshi Inoue, and Tomitarō Horii's South Seas Detachment established a landing force built around the 2nd Battalion, 144th Infantry Regiment, under the command of Major Horie Masao, and a battalion of the Kure Special Naval Landing Force.

To support the operation, the Imperial Japanese Navy formed an escort group under the command of Rear Admiral Kajioka Sadamichi.
To this group, the Japanese assigned the heavy cruisers Aoba, Kinugasa, Furutaka and Kako, the light cruisers Tenryu, Tatsuta, and Yūbari, the destroyers Mutsuki, Mochizuki, Yoyoi, Asanagi, Oite, and Yūnagi.

The invasion fleet left Rabaul on 5 March 1942, consisting of Sadamichi's group, assorted auxiliary vessels, and the transports.
 The troop transports Yokohama Maru and China Maru sailed for Salamaua carrying Horie's troops, while the transports Kongō Maru and Kokai Maru, along with the auxiliary minelayer Tenyo Maru were destined for Lae with the naval landing party.
Air operations were flown by the 24th Air Flotilla around Port Moresby, Lae and Bulolo in support.

Departing Rabaul, the Japanese landed on 8 March 1942 at Lae and Salamaua.
The Horie Unit was assigned the task of capturing Salamaua, including the airfield and township, while the naval landing force was given the responsibility for taking Lae.
At Lae, the Japanese landed without opposition.
A small detachment of the New Guinea Volunteer Rifles and some men from the 2/22nd Infantry Battalion set about the demolition of key infrastructure around Salamaua, and after a minor skirmish which resulted in one Japanese casualty, they destroyed the bridge over the Francisco River and then withdrew into the hills towards Mubo.
Initial air interdiction by Hudsons from No.
32 Squadron resulted in three Japanese killed and eight wounded on the Yokohama Maru.
Another strike by a Hudson around Lae resulted in light damage to the Asanagi.
In early 1942, the Japanese high command began planning operations in the New Guinea and the Solomon Islands, as part of an overall strategy of establishing bases in the South Pacific from which to interdict Allied lines of communication between the US and Australia. As a part of this strategy, it was determined that there was a need to capture Lae, Salamaua, Tulagi and Port Moresby to establish bases, and to prepare for further operations in the South Pacific in order to push a defensive perimeter further south. For the invasion of Salamaua and Lae, the Japanese 4th Fleet, under the command of Shigeyoshi Inoue, and Tomitarō Horii's South Seas Detachment established a landing force built around the 2nd Battalion, 144th Infantry Regiment, under the command of Major Horie Masao, and a battalion of the Kure Special Naval Landing Force.
To support the operation, the Imperial Japanese Navy formed an escort group under the command of Rear Admiral Kajioka Sadamichi. To this group, the Japanese assigned the heavy cruisers Aoba, Kinugasa, Furutaka and Kako, the light cruisers Tenryu, Tatsuta, and Yūbari, the destroyers Mutsuki, Mochizuki, Yoyoi, Asanagi, Oite, and Yūnagi.
The invasion fleet left Rabaul on 5 March 1942, consisting of Sadamichi's group, assorted auxiliary vessels, and the transports.  The troop transports Yokohama Maru and China Maru sailed for Salamaua carrying Horie's troops, while the transports Kongō Maru and Kokai Maru, along with the auxiliary minelayer Tenyo Maru were destined for Lae with the naval landing party. Air operations were flown by the 24th Air Flotilla around Port Moresby, Lae and Bulolo in support.
Departing Rabaul, the Japanese landed on 8 March 1942 at Lae and Salamaua. The Horie Unit was assigned the task of capturing Salamaua, including the airfield and township, while the naval landing force was given the responsibility for taking Lae. At Lae, the Japanese landed without opposition. A small detachment of the New Guinea Volunteer Rifles and some men from the 2/22nd Infantry Battalion set about the demolition of key infrastructure around Salamaua, and after a minor skirmish which resulted in one Japanese casualty, they destroyed the bridge over the Francisco River and then withdrew into the hills towards Mubo. Initial air interdiction by Hudsons from No. 32 Squadron resulted in three Japanese killed and eight wounded on the Yokohama Maru. Another strike by a Hudson around Lae resulted in light damage to the Asanagi.
Invasion of Salamaua–Lae