Kenshiro Abbe (阿部 謙四郎 , Abe Kenshirō , 15 December 1915 – 1 December 1985) was a prominent Japanese master of judo, aikido, and kendo.
 He introduced aikido to the United Kingdom in 1955, and founded the Kyushindo system.
 Abbe was a graduate of the Budo Senmon Gakko, having studied judo and kendo there.
 Following an illustrious early career in the martial arts, he served in the Imperial Japanese Army before and during World War II.
 He then trained in aikido under its founder, Morihei Ueshiba, for a decade.
 Abbe held "dan" ranks in several martial arts, most notably 8th "dan" in judo, 6th "dan" in aikido, and 6th "dan" in kendo.
 After introducing aikido to the UK, he established several Japanese martial arts councils there during the late 1950s.
 He returned to Japan in 1964 and remained there for most of the remainder of his life.
 There are contradictory accounts of Abbe's final years, but it appears that he was in poor spirits and poor health towards the end.
Budo: The Art of Killing is an award winning 1978 Japanese martial arts documentary created and produced by Hisao Masuda and financed by The Arthur Davis Company.
 Considered a cult classic, the film is a compilation of various Japanese martial art demonstrations by several famous Japanese instructors such as Gozo Shioda, Taizaburo Nakamura and Teruo Hayashi.
 Martial arts featured in the film include: karate, aikido, kendo, sumo, and judo among others.
 The only modern Japanese martial art not featured in the film is kyudo.
Kinomichi (氣之道 ) is a martial art in the tradition of budō, developed from the Japanese art aikido by Masamichi Noro and founded in Paris, France, in 1979.
 Masamichi Noro was one of the live-in students ("uchideshi") of Morihei Ueshiba, the founder of aikido.
 Designated "Delegate for Europe and Africa" by Morihei Ueshiba, Noro debarked in Marseille on September 3, 1961, preceding Nakazono and Tamura in the communal construction of a European and African aikido.
 In France, Kinomichi is affiliated with the Fédération Française d’Aïkido, Aïkibudo et Affinitaires (FFAAA) and maintains warm relations with the Aikikai Foundation and its leader, Moriteru Ueshiba, the grandson of aikido’s founder.
Morihei Ueshiba (植芝 盛平 , Ueshiba Morihei , December 14, 1883 – April 26, 1969) was a martial artist and founder of the Japanese martial art of Aikido.
 He is often referred to as "the founder" "Kaiso" (開祖 ) or "Ōsensei" (大先生/翁先生 ) , "Great Teacher".
Morihiro Saito (斉藤 守弘 "Saitō Morihiro", March 31, 1928–May 13, 2002) was a teacher of the Japanese martial art of aikido, with many students around the world.
 Saito's practice of aikido spanned 56 years, from the age of 18, when he first met aikido founder Morihei Ueshiba, until his death in 2002.
Hiroshi Isoyama (磯山博 , Isoyama Hiroshi ) is a Japanese teacher of the martial art of aikido.
 He began training in the Iwama Dojo at the age of 12 as a direct student of the founder of aikido, Morihei Ueshiba in June 1949.
 He currently holds the rank of 8th dan shihan in the Aikikai and is that organization's Technical Councillor.
 Isoyama was made the acting head of the Iwama dojo on behalf of Ueshiba Moriteru following the passing of Morihiro Saito.
 He currently remains as Executive Advisor and senior instructor of that dojo.
Nobuyoshi Tamura (田村 信喜 , Tamura Nobuyoshi , 2 March 1933 in Osaka – 9 July 2010) was a prominent aikidoka and a direct student of Morihei Ueshiba.
 The son of a kendo teacher, Tamura entered the Aikikai Hombu Dojo in 1953 as an uchi-deshi (live-in student) of aikido founder Morihei Ueshiba.
 He was one of Ueshiba's favorite pupils and since 1964 has greatly contributed to the development of aikido in Europe and France in particular.
 He was the National Technical Director (DTN) of the FFAB (French Federation of Aikido and Budō).
 He held the rank of 8th dan and the title of Shihan.
 Throughout his teaching career he trained many others instructors in various countries around the world but foremost Western Europe.
 In 1999, he received the medal of "Chevalier de l'ordre National du Mérite" from the French government.
 Tamura published several books on aikido in French.
 His dojo, Shumeikan Dojo, is located in the village of Bras, France.
Noriaki Inoue (1902-12-03, Tanabe – 1994-04-13, Kunitachi) was a Japanese martial artist, who was in his early years closely associated with the spiritual and technical development of aikido along with his uncle Morihei Ueshiba.
 Inoue is the founder of Shinwa Taidō, a martial art which he later renamed to Shin'ei Taidō.
Aikido (Japanese: 合気道 , Hepburn: aikidō ) ] is a modern Japanese martial art developed by Morihei Ueshiba as a synthesis of his martial studies, philosophy, and religious beliefs.
 Aikido is often translated as "the way of unifying (with) life energy" or as "the way of harmonious spirit".
Daitō-ryū Aiki-jūjutsu (大東流合気柔術 ) , originally called Daitō-ryū Jujutsu (大東流柔術 , Daitō-ryū Jūjutsu ) , is a Japanese martial art that first became widely known in the early 20th century under the headmastership of Takeda Sōkaku.
 Takeda had extensive training in several martial arts (including Kashima Shinden Jikishinkage-ryū and sumo) and referred to the style he taught as "Daitō-ryū" (literally, "Great School").
 Although the school's traditions claim to extend back centuries in Japanese history there are no known extant records regarding the "ryū" before Takeda.
 Whether Takeda is regarded as either the restorer or the founder of the art, the known history of Daitō-ryū begins with him.
 Takeda's best-known student was Morihei Ueshiba, the founder of aikido.

Question: What modern Japanese martial art was developed by Morihei Ueshiba, often referred to as"the founder" "Kaiso" or "Ōsensei"?
Answer: Aikido