Question: While Anatole Litvak and Kinji Fukasaku are both directors, were they both responsible for their own screenplays as well?

Context articles: Tovarich (film)
Battles Without Honor and Humanity: Final Episode
The Fall of Ako Castle
Anatole Litvak
Kenta Fukasaku
The Battle of Russia
Battles Without Honor and Humanity: Proxy War
Kinji Fukasaku
Cops vs. Thugs
Shogun's Samurai

Tovarich (the Russian word for comrade "tovarisch") is a 1937 American comedy film directed by Anatole Litvak, based on the 1935 play by Robert E. Sherwood, which in turn was based on the 1933 French play "Tovaritch" by Jacques Deval.
 It was produced by Litvak through Warner Bros., with Robert Lord as associate producer and Hal B. Wallis and Jack L. Warner as executive producers.
 The screenplay was by Casey Robinson from the French play by Jacques Deval adapted into English by Robert E. Sherwood.
 The music score was by Max Steiner and the cinematography by Charles Lang.
Battles Without Honor and Humanity: Final Episode (Japanese: 仁義なき戦い　完結篇 , Hepburn: Jingi Naki Tatakai: Kanketsu-hen ) is a 1974 Japanese yakuza film directed by Kinji Fukasaku.
 It is the final film in a five-part series that Fukasaku made in a span of just two years.
Swords of Vengeance: Fall of Ako Castle (赤穂城断絶 , Akō-jō danzetsu ) is a 1978 Japanese historical martial arts period film, directed by Kinji Fukasaku.
 It depicts the story of the Forty-seven Ronin ("Chūshingura").
 The film is one of a series of period films by Fukasaku starring Yorozuya Kinnosuke, including "Shogun's Samurai".
Anatole Litvak (Russian: Анато́ль Литва́к ; May 21, 1902 – December 15, 1974) was a Russian-born American filmmaker who wrote, directed, and produced films in various countries and languages.
 He began his theatrical training at age 13 in Leningrad.
Kenta Fukasaku (深作 健太 , Fukasaku Kenta , born September 15, 1972 in Tokyo) is a Japanese filmmaker and screenwriter.
 He is the son of film director Kinji Fukasaku and actress Sanae Nakahara.
The Battle of Russia (1943) is the fifth film of Frank Capra's "Why We Fight" documentary series, and the longest film of the series, consisting of two parts.
 The film was made in collaboration with Russian-born Anatole Litvak as primary director under Capra's supervision.
 Litvak gave the film its "shape and orientation," and the film had seven writers with voice narration by Walter Huston.
 The score was done by Russian-born Hollywood composer, Dimitri Tiomkin, and drew heavily on Tchaikovsky along with traditional Russian folk songs and ballads.
Battles Without Honor and Humanity: Proxy War (Japanese: 仁義なき戦い　代理戦争 , Hepburn: Jingi Naki Tatakai: Dairi Senso ) is a 1973 Japanese yakuza film directed by Kinji Fukasaku.
 It is the third film in a five-part series that Fukasaku made in a span of just two years.
Kinji Fukasaku (深作 欣二 , Fukasaku Kinji , 3 July 1930 – 12 January 2003) was a Japanese film director and screenwriter.
Cops vs. Thugs (県警対組織暴力 , Kenkei tai Soshiki Bōryoku , lit.
 "Police vs. Violence Groups") is a 1975 Japanese yakuza film directed by Kinji Fukasaku.
 It won two Blue Ribbon Awards in 1976: Best Director (Fukasaku) and Best Actor (Sugawara). "
Complex" named it number 6 on their list of The 25 Best Yakuza Movies.
 Kino International released the film on DVD in North America in 2006.
Shogun's samurai (柳生一族の陰謀 , Yagyū Ichizoku no Inbō ) , also known as "The Yagyu Clan Conspiracy" and "Intrigue of the Yagyu Clan", is a 1978 Japanese historical martial arts period film directed by Kinji Fukasaku.
 The film is the first of two period films by Fukasaku starring Shinichi "Sonny" Chiba as Jūbei Mitsuyoshi Yagyū, the other being "Samurai Reincarnation".
 The film was adapted into a teleplay called The Yagyu Conspiracy (柳生一族の陰謀 , Yagyū Ichizoku no Inbō ) that was broadcast by Kansai Telecasting Corporation for 39 one-hour TV episodes from 1978 to 1979.