Johann Jacob Löwenthal, also known as János Löwenthal or Jakab Löwenthal, (born 15 July 1810 in Pest, Austrian Empire; died 20 July 1876 in St. Leonards-on-Sea, England) was a British chess master and chess theorist of Hungarian descent and one of the best players of the 19th century.

He also composed 12 endgame studies (Source: Dutch Website ARVES).

Löwenthal was born in Pest as the son of a Jewish merchant. From 1842 to 1845, he was a member of the Pest Chess Club alongside József Szén and Vincenz Grimm, who played a correspondence match with the leading Parisian masters. After the suppression of the revolution of 1848/49, Löwenthal left Hungary to emigrate. He lived for some time in the United States, where he met and sensationally defeated the 13-year-old Paul Morphy.

In 1851, he took part in the first international chess tournament in history, held on the occasion of the Great Exhibition in London. He was defeated in the first round by Elijah Williams, but remained resident in England and became British. In 1853 he played a dramatic match with Daniel Harrwitz, who now played chess for a living. This is remembered for the fact that Löwenthal squandered a 9-2 lead to lose 10-11. Löwenthal won the important tournaments in Manchester in 1857, where he outplayed Adolf Anderssen (knockout system), and in Birmingham in 1858, where he beat Howard Staunton 2-0 (also knockout system). That year Morphy visited Europe and met the British champions in London. Löwenthal, who was full of admiration for the young American champion and became his first biographer, played a match with him, which he lost 4.5:10.5 (+3 =4 -9). 

 Paul Morphy, who was financially independent, gave his friend Löwenthal his prize money (£100) in the form of a complete set of furniture, for which he even added another £20.

He accepted the position of secretary of the St John's Chess Club in London and invented the chess demonstration board. His work at the club brought him the acquaintance of many prominent and wealthy Britons. From 1863 to 1868 he worked as editor of the Chess Player's Magazine and was responsible for the chess columns of the newspapers Era, Family Herald, The Illustrated News of the World and The Glowworm.

When Löwenthal fell seriously ill in 1874 and earning money was out of the question, the politician Lord Randolph Churchill set up a relief fund for the champion, who died on 24 July 1876 near the town of Hastings. The "Löwenthal Cup", the trophy for the English national championship, is named after him.

Löwenthal's best historical Elo rating was 2616, which was determined for June 1859. From October 1858 until that date, he was ranked second in the retrospectively calculated world rankings.

Contribution to chess composition
As chess editor of the English weekly magazine The Era, Löwenthal organised the first international composition tournament in 1856. He appointed a committee of well-known English and German problemists to organise it; the final judges were Ernst Falkbeer, Walter Grimshaw, Bernhard Horwitz, Josef Kling, Charles Ranken and Henry Turton, and the arbiter was Silas Angas.

Each composer was asked to send in six problems; self-mates and conditional problems were excluded. The tasks were assessed blind: They were labelled with a motto, in a sealed envelope the motto was linked to the name of the submitter. The prize was not awarded for an individual task, but for the entire set submitted. The participants included Conrad Bayer, Frank Healey, Rudolph Willmers and Anton Nowotny. The first prize went to Conrad Bayer and the second to Frank Healey. Löwenthal also wrote the tournament book.

The Era Tournament was not the first chess problem tournament ever (a small English composition tournament had taken place in 1854, which had been won by Walter Grimshaw), but it had a strong impact due to its international participation and good documentation. Following its example, other organisations and magazines organised similar competitions, such as the American Chess Congress in 1857, La Régence in 1860 and the British Chess Association in 1861.

Others: On the Dutch Website ARVES are 6 endgame studies by Löwenthal selected.

Sources: Germain Wikipedia

                Website ARVES.org