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Sicilian Defence

The Sicilian Defence is a chess opening that begins with the moves:

The Sicilian is the most popular and best-scoring response to White's first move 1.e4. 1.d4 is a statistically more successful opening for white due to the high success rate of the Sicilian defence against 1.e4.New In Chess stated in its 2000 Yearbook that of the games in its database, White scored 56.1% in 296,200 games beginning 1.d4, but 54.1% in 349,855 games beginning 1.e4, mainly due to the Sicilian, which held White to a 52.3% score in 145,996 games.

17% of all games between grandmasters, and 25% of the games in the Chess Informant database, begin with the Sicilian. Almost one quarter of all games use the Sicilian Defence.

Grandmaster John Nunn attributes the Sicilian Defence's popularity to "its combative nature; in many lines Black is playing not just for equality, but for the advantage. The drawback is that White often obtains an early initiative, so Black has to take care not to fall victim to a quick attack." Grandmaster Jonathan Rowson considered why the Sicilian is the most successful response to 1.e4, even though 1...c5 develops no pieces, and the pawn on c5 controls only d4 and b4. Rowson writes:

Planck charge

In physics, the Planck charge, denoted by , is one of the base units in the system of natural units called Planck units. It is a quantity of electric charge defined in terms of fundamental physical constants.

The Planck charge is defined as:

where:

The Planck charge is times larger than the elementary charge e carried by an electron.

The Gaussian cgs units are defined so that , in which case has the following simple form:

It is customary in theoretical physics to adopt the Lorentz–Heaviside units (also known as rationalized cgs). When made natural () they are like the SI system with . Therefore it is more appropriate to define the Planck charge as

When charges are measured in units of , i.e., when is set equal to 1, we obtain , which is commonly used in theoretical physics. In contrast, in (non-rationalized) natural cgs units where we have .

See also

Notes and references