Pins

183.000 unique visitors followed the live broadcasting of the chess.com blitz final. Normally I am not interested in blitz or rapid but this time also I was glued to my screen to see the spectacle between Carlsen and Nakamura. The only bad point in the otherwise well organized match was the inability of the moderators to remove the many attacks of trolls. Even the commentators got visibly annoyed and experienced troubles to keep their focus on the games.

It is a recurring problem we encounter at many websites where you can respond anonymously. You always meet people eager to create chaos and frustration. They get thrilled by the power to control a conversation. It is doubtless also the main reason why we see today very few interesting comments anymore in comparison with the very first years of the internet.

It is not at all difficult to hijack a discussion even if you know very little or nothing about the subject. To express your opinion as a fact is a very often used method. To destabilize the credibility of somebody is another one. To focus on grammatical errors, semantic elements or tiny insignificant details is also a well known technique. As a highly experienced poster with 18 years of experience with many forums I have of course met my share of impostors.

The easiest is to ignore them and this is often necessary but sadly only creates a empty dessert of silence. Therefore I prefer to carefully select the terms I still want to continue the discussion. This strategy is not always appreciated especially if my discussion partner finds some points which I ignore rather important.

With this special introduction I want to link to a reaction upon my article X-Ray attacks. I don't think we deal here with a troll but the reaction does talk only about a technical detail. What is the different between a x-ray attack and a pin? I don't own the truth concerning chess-terminology but personally I believe there exists an essential difference between both. A pin is something static while an x-ray attack is dynamic. I mean in a x-ray attack we see the defense moving while this is not the case in a pin.

Maybe the confusion is created by the many themes around pins from the world of compositions. In those we also see movements of even the piece which is pinned as in the problem below made by myself.

Mate in 2

White plays the piece which is pinned. To counter the mate-threat, black unpins this piece.

A more complicated theme is the next problem.

Mate in 2

Again white plays with the pinned piece but this time we notice that the threat consists of unpinning a black piece. Black counters by unpinning the pinned piece. This is called the Kagan theme.

In both examples we see movements but the pins stay and can only be released by the other color controlling the pin. That is an important difference compared to x-ray attacks in which the pinned party still can decide for themselves to remove the pin although often leading to material losses.

Brabo

Solutions

Position 1:

1. Rf5 threatens 2.Nd4#

1. ... Qf6~ (unpins the rook) 2. Rc5#
1. ... e7~ 2.Qc5#
1. ... d7~ 2.Qe8#
1. ... b7~ 2.Qa8#
1. ... Nb5 2.cxb5#
1. ... fxg6 2.Bd5#

Position 2:

1. Rd2 threatens 2.Qa1# (unpins the queen)
1. ... Qe2~ (unpins the rook) 2. Rd5#
1. ... Rxd6 2.Bd6#
1. ... Ng3~ 2.Rf5#