King's Gambit Accepted: Kieseritzky Gambit, Berlin Defense, de Riviere Variation

In the King's Gambit Accepted: Kieseritzky Gambit, Berlin Defense, de Riviere Variation, white starts with e4, which is a common move in many chess openings. This move opens up the center and allows white to control the board's important squares. By controlling the center, white can apply pressure on black and keep their pieces active. Additionally, e4 allows for the possibility of casting early, further strengthening white's position and leading to a strong attack. However, by playing this move, white also sacrifices a pawn.

The move e5 by Black is a common response to e4, as it also opens up the center and creates space for Black's pieces. It aims to control the central squares, cede no space to white, and lay the foundation for equal development. It also clears the way for Black's light-squared bishop and queen to enter the game and exert their influence. However, by playing e5, Black also risks losing their pawn, particularly if they don't manage to secure control of the center.

The move f4 by White is known as the King's Gambit, which is an aggressive opening that aims to control the center with pawns and seize the initiative. By playing f4, White is opening up the possibility of sacrificing the f-pawn in exchange for attacking chances. It lures Black to take the pawn and create a weakness in their kingside. Additionally, f4 puts pressure on Black's e5 pawn, which may force them to spend moves defending it. However, playing f4 also weakens White's king position and option for castling kingside.

In the King's Gambit Accepted: Kieseritzky Gambit, Berlin Defense, de Riviere Variation, Black responds to White's f4 with exf4, accepting the gambit pawn and opening up lines for their pieces. By taking the f4 pawn, Black gains a temporary material advantage and forces White to come up with a plan to regain the lost pawn. Additionally, exf4 weakens White's control over the center and leaves their king exposed to possible attacks. However, accepting the gambit pawn also comes with drawbacks, such as giving up time and exposing Black's own king.

In response to Black's exf4, White plays Nf3, developing their knight and preparing to castle kingside. By playing Nf3, White also puts pressure on Black's pawn on e5, which may force Black to spend moves defending it. Additionally, Nf3 prepares for the possibility of pushing the g-pawn to attack Black's knight on f6. Playing Nf3 also avoids the possibility of Black playing Qh4 and threatening White's pawn on h2. However, by playing Nf3, White cannot immediately recapture the gambit pawn on f4 and hence has to come up with a plan to regain it.

In response to White's Nf3, Black plays g5, a move that creates an escape square for their king and gains space on the kingside. Additionally, g5 puts pressure on White's knight on f3, which may force it to move or risk being captured. Playing g5 also opens up the possibility of Black playing h6 to further restrict White's knight's movement and prepare to castle kingside. However, by playing g5, Black weakens their kingside pawn structure and creates a potential weakness on the g-file that White can use to attack Black's king.

In the King's Gambit Accepted: Kieseritzky Gambit, Berlin Defense, de Riviere Variation, White plays h4 in response to Black's g5. The move h4 gains space, threatens to push Black's g-pawn further down the board and opens up the h-file for White's rook. Additionally, playing h4 prepares for the possibility of sacrificing the knight on f3 to open up lines of attack against Black's king. By playing h4, White also restricts Black's pawn push to h6 and can keep up the pressure with further pawn advances on the kingside. However, h4 also weakens White's kingside pawn structure, leaving the pawn on h4 vulnerable to attack and opening up the possibility of a counterattack by Black.

In response to White's h4, Black plays g4, counterattacking White's pawn chain and forcing White to make a decision. G4 gains space on the kingside and opens up lines for Black's pieces. By playing g4, Black also threatens to attack White's knight on f3, which may force it to retreat or risk being captured. Additionally, g4 can help Black's king to evacuate to the kingside if necessary. However, by playing g4, Black weakens their own pawn structure and leaves their king more exposed to potential attacks by White's pieces.

In response to Black's pawn push to g4, White plays Ne5 with the intention of regaining the pawn on g4 and controlling key squares in the center. Ne5 also puts pressure on Black's knight on f6, which may make it hard for Black to recapture the knight on e5. By playing Ne5, White also prepares to castle kingside and further develop their pieces towards the center while taking advantage of doubled pawns on Black's g-file. However, playing Ne5 also exposes White's knight to potential attacks by Black's pawns or pieces, forcing White to defend the knight and come up with a solid plan to follow up.

In the King's Gambit Accepted: Kieseritzky Gambit, Berlin Defense, de Riviere Variation, Black plays Nf6 in response to White's Ne5. By playing Nf6, Black develops their knight while attacking White's knight on e5. Nf6 also prepares for the possibility of playing d5 and further attacking White's knight. Additionally, Nf6 defends Black's pawn on e5 and reinforces Black's control over the center. By developing their knight to f6, Black also prepares to castle kingside and strengthen their position, all while keeping White's knight in check. However, playing Nf6 also exposes Black's king, leaving it open to potential attacks by White's pieces.

In response to Black's Nf6, White plays Nxg4, capturing the f6 knight and further opening up lines of attack against Black's king. Nxg4 also increases the pressure on Black's pawn on e5 and weakens Black's pawn structure. White can potentially follow up with moves like Qe1 or Qh5, introducing further threats to Black's position. By playing Nxg4, White also takes advantage of Black's exposed position, leaving their king open to potential attacks involving both white pieces and pawns. However, this move also comes at the cost of temporarily sacrificing White's knight, leaving it vulnerable to potential retaliation by Black's remaining pieces.

In response to White's capture on g4, Black plays d5, immediately targeting White's knight on f3 and aiming to open up the center. By playing d5, Black frees up their light-squared bishop and puts pressure on White's pawn on e4. Additionally, pushing the pawn to d5 takes control of the central squares and allows Black to further develop their pieces. Playing d5 also exposes the possibility of capturing White's knight on c3 with their bishop, further disrupting White's pawn structure. However, playing d5 may also lead to an open position where both kings are exposed, so Black needs to be careful in their play.