Basic checkmates are positions in which one side has only a king and the other side has one or two pieces, enough to checkmate the opponent's king. They are usually learned at the beginner stage. Examples are mate with K+Q v K; K+R v K; K+2B v K; K+B&N v K (this one is quite difficult).
There are two types of chess programs. One is to play against you; the other is to help you become a better player by learning more. The two types can be made to work together, though they have different functions.
Chess engines are computer systems that can play chess games against human opponents. Quite a number have been devised; they can play at master level, though their processes are quite different from a human being.
Fritz is a German chess program by Frans Morsch and Mathias Feist, published by ChessBase. It is the current market leader. There is also a different kind of Fritz called "Deep Fritz" that is made for multi-processing. The latest kinds of the consumer products are Deep Fritz 12 and Fritz 12. They came with reviews by Josh Waitzkin, who said that "Fritz is like a woman that you can't get with. It just drives (makes) you to think in ways you've never thought before".
Shredder, also a ChessBase product, is claimed to be the strongest engine at present.
Rybka, a product by Vasik Rajlich, is Shredder's main rival.
Chess databases do not actually play. They give access to the recorded history of master chess. There are two components. First, there is the software, which lets one search and organise the database material. Then there is the actual database, typically one to four million games.
In practice, databases are used for two purposes. First, for a player to train his/her ability at specific openings. Second, to look up specific opponents to see what they play, and prepare against them beforehand.
The existence of chess databases is one of the reasons young players can achieve mastery at an early age.
ChessBase is the biggest database, and widely used by masters. Although it can be used online, most users download the software and data onto their computer. If that computer happens to be a laptop, then they might take the laptop to tournaments, to help prepare for games. Players may not use computers or any other aid during games, but much preparation goes on behind the scenes. ChessBase has to be purchased, and it is not cheap.
This is a Dutch magazine for advanced players, which runs an on-line database called NicBase as part of its services. NicBase is free, and has over a million games.
Chessgames.com runs an on-line database of games. It is partly free, but requires registration. Full access to all its facilities is by a fairly modest subscription. It has over half a million games on its database.
There are websites which a player can join (for a fee) and play on line. In this case, the subscriber will play against other subscribers, not a computer. All standards of players are amongst the members, and various events are on offer at different rates of play. The two leaders in this market are:
These are endgames for improvers, based on reviews by John Watson.
Gold
Gold is a soft, dense, yellow metal. It is a chemical element. Its chemical symbol is Au. Its atomic number is 79. As a precious metal, it has been used for many thousands of years by people all over the world, for jewelry, and as money. Gold is important because it is rare, but also easier to use than other rare metals. It is also used to repair and replace teeth and in electronic equipment such as computers. The color of this metal is also called "gold".
Mining methods for gold are similar to other metals. Gold is so valued that the discovery of a new place to mine has sometimes caused a gold rush. The deepest workplaces for miners in the world are in South African gold mines.
Often, gold is found as a native metal. This means it is not part of an ore, and does not need smelting. It may be in large, pure nuggets but more often must be separated from other minerals and soil.
Most of the gold on Earth is deep inside the Earth's core because it is dense. Nearly all discovered gold was deposited on the surface by meteorites.
In chemistry, gold is chemical element 79, a transition metal in Group 11. It has an atomic weight of 199.966 a.m.u. Its symbol is Au, from the Latin word for gold, "aurum". It is a "noble metal" meaning it has low chemical reactivity.
Gold is very soft. It is malleable, meaning a goldsmith can hammer it into thin metal sheets. It is also ductile, which means it can be pulled into wire. When it is used in money or in jewelry, it is often alloyed with silver or some other metal to make it harder.
Most metals are gray in color. Gold is yellow because of the way its electrons behave. The only other metal in common use that has a non-gray color is copper. Caesium also has a gold-like color, but it is not commonly used as a metal because it reacts with water.
Gold is a fairly good electrical conductor, but not as good as copper or silver. Copper and brass electrical connectors, especially those used with computer and audio/video equipment, are often plated with gold for corrosion resistance.
Gold can mean that something or someone is very good or has done very well. A gold medal is often the given to the first-place winner in a race or other sports. Something that is in some way good may be given gold status.
Metallic gold is non-toxic, which is unusual for a heavy metal. Soluble gold compounds, however, are toxic to the liver and kidneys. Gold is non-flammable, even in a pure oxygen environment or when finely powdered. It does not react with most household or laboratory chemicals. Gold is commonly processed with cyanide, which is highly toxic. Most of the cyanide is destroyed in the production process, so it is not present in the final product, but it can be a hazard to workers in a gold processing plant. Since gold conducts electricity, gold jewelry should never be worn when working with electricity.
Century
A century is a way to describe a length of time. One century is one hundred years. The ancient Romans used the word "centuria" to describe a group of about one hundred soldiers, organized into a single unit.
The Roman numeral for 100 is "C". The word for 100 in Latin is "centum".
A centenary is a celebration of something that happened 100 years ago. A bicentenary celebrates 200 years, a tercentenary 300 years.
A centenarian is someone who is 100 years old or more.
Centennial means something that happens every 100 years, or that lasts 100 years.
Kilogram
The kilogram is the base unit of mass in the International System of Units (SI). It is in widely used in science, engineering, and commerce worldwide. The kilogram is exactly the mass of one litre of water.
As of May 20, 2019, the definition of the kilogram is based on the Planck constant as .
There are attempts to define the kilogram in other ways. One example specifies a number of atoms of a certain substance (at a certain temperature).
One kilogram is a little more than 2.2 pounds. One tonne is one thousand kilograms. One litre of water weighs almost exactly one kilogram, at , at sea level. This was the basis of the definition of the gram in 1795.
In 1879, the piece of metal was made. It was officially chosen to be the kilogram in 1889. It was made of 90% platinum and 10% iridium. Those metals were chosen because they do not rust or corrode like most metals. It is stored in a vault at the BIPM in Sèvres, France. From 1795 to 1799, the unit of mass was not called "kilogram" but was called "grave".
The original kilogram is kept inside bell jars. Over time, dust can collect on it. Before it is measured, it is cleaned to get the original size.
The kilogram is a unit of mass. In normal language, measuring mass defines how "heavy" is something. This is not scientifically correct. Mass is an "inertial property". It measures the tendency of an object to stay at a given speed when no force acts on it.