Sasanian EmpireThe Sasanian Empire (səˈsɑːniən,_səˈseɪniən), officially known as Eranshahr ("Land/Empire of the Iranians"), was the last Iranian empire before the early Muslim conquests of the 7th–8th centuries AD. Named after the House of Sasan, it endured for over four centuries, from 224 to 651 AD, making it the longest-lived Persian imperial dynasty. The Sasanian Empire succeeded the Parthian Empire, and re-established the Persians as a major power in late antiquity alongside its neighbouring arch-rival, the Roman Empire (after 395 the Byzantine Empire).
Glossary of chessThis glossary of chess explains commonly used terms in chess, in alphabetical order. Some of these terms have their own pages, like fork and pin. For a list of unorthodox chess pieces, see Fairy chess piece; for a list of terms specific to chess problems, see Glossary of chess problems; for a list of named opening lines, see List of chess openings; for a list of chess-related games, see List of chess variants; for a list of terms general to board games, see Glossary of board games.
MathematicsMathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics with the major subdisciplines of number theory, algebra, geometry, and analysis, respectively. There is no general consensus among mathematicians about a common definition for their academic discipline. Most mathematical activity involves the discovery of properties of abstract objects and the use of pure reason to prove them.
RussiaRussia (Rossiya, rɐˈsjijə), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world by area, its vast landmass stretching over the easternmost part of Europe and the northernmost part of Asia. Russia extends across eleven time zones and shares land boundaries with fourteen countries. It is the world's ninth-most populous country and Europe's most populous country. The country's capital and largest city is Moscow.
ChinaChina (), officially the People's Republic of China (PRC), is a country in East Asia. It is the world's second-most populous country with a population exceeding 1.4 billion. China spans the equivalent of five time zones and borders fourteen countries by land, tied with Russia as having the most of any country in the world. With an area of nearly , it is the world's third largest country by total land area. The country consists of 22 provinces, five autonomous regions, four municipalities, and two semi-autonomous special administrative regions.
Saint PetersburgSaint Petersburg, formerly known as Petrograd (1914–1924) and later Leningrad (1924–1991; see below), is the second-largest city in Russia after Moscow. It is situated on the Neva River, at the head of the Gulf of Finland on the Baltic Sea. The city had a population of roughly 5.6 million residents as of 2021. Saint Petersburg is the fourth-most populous city in Europe, the most populous city on the Baltic Sea, and the world's northernmost city of more than 1 million residents.
ChessboardA chessboard is a used to play chess. It consists of 64 squares, 8 rows by 8 columns, on which the chess pieces are placed. It is square in shape and uses two colours of squares, one light and one dark, in a chequered pattern. During play, the board is oriented such that each player's near-right corner square is a light square. The columns of a chessboard are known as , the rows are known as , and the lines of adjoining same-coloured squares (each running from one edge of the board to an adjacent edge) are known as .
Game theoryGame theory is the study of mathematical models of strategic interactions among rational agents. It has applications in all fields of social science, as well as in logic, systems science and computer science. The concepts of game theory are used extensively in economics as well. The traditional methods of game theory addressed two-person zero-sum games, in which each participant's gains or losses are exactly balanced by the losses and gains of other participants.
World Chess ChampionshipThe World Chess Championship is played to determine the world champion in chess. The current world champion is Ding Liren, who defeated his opponent Ian Nepomniachtchi in the 2023 World Chess Championship. Magnus Carlsen, the previous world champion, declined to defend his title. The first event recognized as a world championship was the 1886 match between the two leading players in the world, Wilhelm Steinitz and Johannes Zukertort. Steinitz won, becoming the first world champion.
Correspondence chessCorrespondence chess is chess played by various forms of long-distance correspondence, traditionally through the postal system. Today it is usually played through a correspondence chess server, a public internet chess forum, or email. Less common methods that have been employed include fax, homing pigeon and phone. It is in contrast to (OTB) chess, where the players sit at a chessboard at the same time, or play each other in real time via the internet.
