Nihonkai daikaisen (日本海大海戦, Battle of the Japan Sea) is a 1969 Japanese war drama film directed by Seiji Maruyama and produced by Tomoyuki Tanaka. Set between 1904 and 1905, Japan and
Russia clash in what comes to be known as the Russo-Japanese War. An attempt by the Japanese fleet and army to take Port Arthur fails, and a Russian fleet bears down on the Sea of Japan.

Veteran screenwriter Toshio Yasumi wrote the script and Seiji Maruyama (who had filmed Rengo kantai shirei chôkan: Yamamoto Isoroku in 1968) directed the film. Special effects director Eiji Tsuburaya of "Destroy All Monsters" worked on the set and Hiroshi Murai of "Nikudan" was in charge of filming the scenes.

The concurrent screening work is "Konto 55-Gō jinrui no dai jakuten", directed by Jun Fukuda.

Overview 
It is said to be the third work in the "Toho 8/15 series", but unlike the two previous war films, this one take place during the Russo-Japanese War. From the beginning of the war, to General Nogi Maresuke's troops attack Port Arthur, and the combined fleet led by Admiral Togo Heihachiro at the Battle of Tsushima to defeats the Baltic Fleet led by Vice Admiral Zinovy Rozhestvensky.

Special Effects 
This work was the last film in which Eiji Tsuburaya participated it as special effects director. The ship miniature mobilized 60 art designers and 107 ships were prepared for the movie.

In addition, the miniature of the battleship Mikasa was made up to 13 meters.

In the naval battle scene, considering that the power of the bullets is weaker at the time of the Russo-Japanese War than during the Pacific War, the water column is expressed by freon gas.

Plot 
During the late 19th century, the Qing dynasty continued to desinegreated in turmoil due to corruption, peasant unrest, ruler incompetence, and population growth which led to food shortages and regular famine. In 1900 during the Boxer Rebellion, the Eight Nation Alliance (Britain, United States, Germany, France, Russia, Japan, Italy and Austria-Hungary) joined forces together to occupied many ports and cities in China. However, only Russia kept its troops in Manchuria and setting up their railway line which caused tensions with Japan over the sphere of influence.

At the Imperial Conferences meeting with Emperor Meiji, they sent an ultimatum to recognize Russian dominance in Manchuria in exchange for recognition of Korea being within the Japanese sphere of influence.Finally, diplomatic relations between two countries began to get even hostility. Togo Heihachiro, Admiral of the Fleet in the Imperial Japanese Navy, was eyeing on Lushunkou (aka Port Arthur) and the movement of the Russian Pacific Fleet in Vladivostok, and devised a secret plan. Then, he got reports that Captain Takeo Hirose, commanded the old cargo vessel Fukui Maru and several ships, was spotted by the Russian fleet squadron and was hit, destroying the ship and killing Hirose. Many officers and sailors managed to escape from the Battle of Port Arthur. War was declared after the first naval battle. The Japanese Navy won its first battle against the Russians.

In the meantime, Japanese troops deployed from Korea to Manchuria. The First Army under General Kuroki Tamemoto landed on Incheon to occupied Seoul and began marching north to meet the Russian army at the Yalu River. After defeating them, the Third Army led by General Nogi Maresuke march on to Port Arthur and began the siege. However, the Russian Navy was unable to relived the siege after they were defeated again by the Japanese squadron at Chemulpo Bay. On October 20, the Baltic Fleet left the port of Rabaul.

Togo decided that the enemy ships would appear in the Sea of ​​Japan and dragged the combined fleet inland. On New Year's Day, five months after the attack began, General Nogi planned an attack on 203 Hill, trying to captured the fortress. However, the commander of Port Arthur Anatoly Stessel managed to hold off the attack by setting up machine guns, artillery positions, land mines, and searchlights. The Japanese would continued to attack the fortress until the defense commander Roman Kondratenko was killed by an artillery shells and Stessel had no choice but to surrendered the fortress to General Nogi.

Around this time, Akashi Motojiro, an intelligence officer in Stockholm (Sweden), learned that the route of the Baltic Fleet would be determined by Russian Vice Admiral Zinovy Rozhestvensky. But on the way, they attack a On May 20, the surveillance ship Shinano Maru discovered the Baltic Fleet headed off to the Goto Islands. Seven days later, Admiral Togo, who hoisted the Z flag on board the flagship Mikasa, took an intrepid tactic that took a big turn in front of the Russians and tightened the enemy's front. A fierce battle at Tsushima brought a great victory to the Japanese fleet. People of Japan who are excited about victory and the Russians are forced to surrendered in the Treaty of Portsmouth on September 5, 1905. This result Russia turn into a bloody revolution by mass demonstrations over the defeat and labor dispute.  However, Togo could not forget the true "fear of battle" by winning the war.

Staff 

 Producer: Tomoyuki Tanaka
 Director: Seiji Maruyama
 Special Effects: Eiji Tsuburaya (special effects director), Noriyoshi Inoue (special effects art director), Yôichi Manoda (special effects cinematographer), Hiroshi Mukoyama (matte compositions), Fumio Nakadai (wire manipulator), Teruyoshi Nakano (special effects assistant), Yoshiyuki Norimasa (matte process photography), Motoyoshi Tomioka  (special effects cinematographer)  (credited as Sokei Tomioka)
 Screenwriter: Toshio Yasumi
 Cinematographer: Hiroshi Murai
 Composer: Masaru Sato
 Sound Department: Minoru Kaneyama (sound effects editor), Noboru Yoshioka (sound recordist)
 Camera and Electrical Department: Toshio Takashima (lighting technician), Iwao Yamazaki (still photographer)
 Production Designer: Takeo Kita

Cast 

 Toshiro Mifune as Tōgō Heihachirō (Commander-in-Chief of the Combined Fleet)
 Yūzō Kayama as Major Takeo Hirose
 Tatsuya Nakadai as Colonel Akashi Motojiro
 Toshio Kurosawa as First Class Soldier Miyoshi Maeyama
 Ban Kojika as Magoshichi Sugino
 Keiji Higashiyama as Mr. Fujimoto
 Akira Kubo as Kikuisami Matsui (based on Kikuisami Matsumura)
 Makoto Satō as Chief of Artillery Kiyokazu Abo
 Susumu Fujita as Admiral Kamimura Hikonojō
 Akihiko Hirata as Staff Officer Koreshige Tsunoda
 Yoshio Tsuchiya as Staff Officer Akiyama Saneyuki 
 Jun Funato as Staff Officer Kumaji Yamaoka
 Kenji Sahara as Deputy Director of Shinano Maru, Hikosaburo Maruhashi
 Yoshifumi Tajima as Colonel Hikojirō Ijichi
 Hiroshi Koizumi as Ministry of Foreign Affairs Shin'ichirō Kurino 
 Jun Tazaki as Shimaji Hashiguchi (Miyakojima islander)
 Eijiro Yanagi as Itō Hirobumi
 Takeshi Katō as Chief of Staff Katō Tomosaburō
 Toru Abe as Lieutenant Colonel Genjiro Suji  (1st Regiment of Konoe Infantry)
 Masao Shimizu as Director the Navy Totsuka Tamaki
 Gen Shimizu as Colonel Akira Narukawa
 Ryuji Kita as Admiral Kataoka Shichirō
 Kanta Mori as Chief of Staff Ijichi Kōsuke
 Gen Takamori as Major Nagata Yasujirō
 Haruo Nakajima as Staff of the First Fleet (uncredited)
 Seiji Matsuyama as Matsu (Miyakojima youth)
 Shin Tatsuoka as Minister for Foreign Affairs of Japan Inoue Kaoru
 Takamaru Sasaki as Advisor Kuki Ryūichi
 Kiyoshi Kodama as Captain Yamamoto Shinjiro
 Yoshio Inaba as Chief of Staff Shimamura Hayao
 Ken Mitsuda as President of the Japanese Privy Council Yamagata Aritomo
 Kose Itaru as Lieutenant Colonel Kariba Umi
 Jun'ichirô Mukai, Naoya Kusakawa as Staffs of the 1st Fleet
 Shigeo Katô as Public speaker, Miyakojima residents (uncredited)
 Akio Kusama as Minister, Resident who sees off the Hitachi Maru (uncredited)
 Yasuo Araki as Major Yamagata
 Toyohiko Sata as Fisherman Hayafune
 Kōji Iwamoto as Hitachi Maru officer
 Kazuo Suzuki as Miyakojima fisherman
 Chôtarô Tôgin as Ship gunner 
 Seishirō Kuno as Lieutenant Tsukamoto
 Kenzaburô Ôsawa as Artillery gunner
 Ken Echigo (Mikasa staff officer)
 Yutaka Oka as Commander of the Shiroda Sukitai (White Coat) team
 Yōko Yano as Matsu's wife
 Noriko Honma as Old woman at a candy store
 Ted Gunther as Shriax
 Jacob Japiro as Informant
 Harold Conway as Captain John Campbell
 Osman Yusuf as Russian naval officer
 Peter Williams as Commander Nikolai Nebogatov
 Andrew Hughes as Admiral Zinovy Rozhestvensky (General Commander of Baltic Fleet)
 Hans Horneff as Admiral Nikolai Kolomeitsev 
 Robert Dunham as Aide to Admiral Alekseyev (uncredited)
 Ralph Jesser as Staff Officer of the Baltic Fleet  
 Ryutaro Tatsumi as Minister of Navy Yamamoto Gonnohyōe
 Mitsuko Kusabue as Kaeda Tetsu
 Chishū Ryū as Nogi Maresuke
 Matsumoto Hakuō I as Emperor Meiji
 Masaaki Yajima as Narrator * Non-credit

Video software 
The DVD version of the film was released by Toho Video on June 21, 2001.