Intentional foul on throw in
 

In the case of any type of throw-in, when is a foul intentional? Meaning a foul that would normally be common but by rule must be intentional?

I don't have my books with me and was asked this question about throw-ins and thought I remembered the foul must be intentional bus wasn't sure.

The same rules / guidelines apply. If it's a "basketball play" it's lilley not intentional; if it's not a basketball play, it likely is.

If they reach across the boundary plane and foul the thrower before the ball is released, it's intentional by rule.

If the defender reaches through the plane and contacts the thrower, it's an intentional foul, no warning needed

Correct, but you call the intentional foul and issue the official warning.

Sent me to the rule book, so I'll post this:

What first confused me is remembering that if the defender reaches across the plane and touches the ball while still in possession of the thrower it is a technical foul... unexpected that contacting the thrower would be an intentional foul while contacting the ball would be a technical:

[edited for "Penality"!?!]

10.3.11 SITUATION A: After a field goal, A1 has the ball out of bounds for a throw-in. Thrower A1 holds the ball: (a) B2 crosses the boundary line and fouls A1; or (b) B2 reaches through the out-of-bounds plane and touches the ball while in the hands of A1. RULING: It is an intentional personal foul in (a), and a technical foul in (b). In (a), such a contact foul with the thrower during a throw-in shall be considered intentional, or if it is violent, it should be ruled flagrant. COMMENT: Either act is a foul and it should be called whenever it occurs during a game without regard to time or score or whether the team had or had not been warned for a delay-of-game situation. If the player making the throw-in (A1) reaches through the out-of-bounds plane into the court and B1 then slaps the ball from the hand of A1, no violation has occurred. B1 has merely slapped a live ball from the
hands of A1. (4-19-3, 4; 9-2-11 Penalty 3, 4)


Yep.
10.3.11 SITUATION C: Team A scores near the end of the fourth quarter and is trailing by one point. B1 has the ball and is moving along the end line to make the throw-in. A2 steps out of bounds and fouls B1. Is the foul personal or technical? RULING: This is an intentional personal foul. The time remaining to be played or whether Team A had been previously warned for a delay-of-game situation is not a factor. If the team had not been warned, the foul constitutes the warning. (4-19-1; 9-2-11 Penalty 4)

9.2.11 SITUATION: A1 is out of bounds for a throw-in. B1 reaches through the boundary plane and knocks the ball out of A1's hands. Team B has not been warned previously for a throw-in plane infraction. RULING: B1 is charged with a technical foul and it also results in the official having a team warning recorded and reported to the head coach. ...

My thought on this question is at the end of a game when the team trailing is trying to foul, so they foul before the ball is inbounded, basketball play or not. Is it a common foul or intentional?

Ask and ye shall receive... :)

2006-07 POINTS OF EMPHASIS

4. Intentional Fouls. The committee continues to be concerned about how games end. While there has been some improvement in the application of the rule, there is still need for further understanding and enforcement. An intentional foul is a personal or technical foul that neutralizes an opponent's obvious advantageous position. Contact away from the ball or when not making a legitimate attempt to play the ball or player, specifically designed to stop or keep the clock from starting, shall be intentional. Intentional fouls may or may not be premeditated and are not based solely on the severity of the act. A foul also shall be ruled intentional if while playing the ball a player causes excessive contact with an opponent.
Fouling is an accepted coaching strategy late in the game. There is a right way and a wrong way to foul. Coaches must instruct their players in the proper technique for strategic fouling. "Going for the ball" is a common phrase heard, but intentional fouls should still be called on players who go for the ball if it is not done properly.
Additionally, in throw-in situations, fouling a player that is not involved in the play in any way (setting a screen, attempting to receive the in-bound pass, etc. ) must be deemed intentional. Far too often, officials do not call fouls as intentional when the act clearly meets the criteria.

It had better look good, IMO. It had better really look like a legitimate play.

As Nevada's quote indicates, you call intentional if the fouled player is not involved in the play. A player is involved in the play if they are setting a screen, attempting to receive the pass, etc. An example of a player not in the play is one 50' down the court just waiting for the guards to inbound the ball and bring it down court. (Some have contended that the parenthetical expression is giving examples of player NOT involved in the play but they are simply comprehension challenged...it is a list of actions deemed to be part of the play).

Boundary Plane
 

The defender may not break the imaginary plane during a throwin. If the defender breaks the imaginary plane during a throwin, the defender’s team will receive a team warning, or if the team has already been warned for one of the four delay situations, this action would result in a team technical foul. If the defender contacts the ball after breaking the imaginary plane, it is a player technical foul and a team warning will be recorded. If the defender fouls the inbounding player after breaking the imaginary plane, it is an intentional personal foul, and a team warning will be recorded.

Just remember that a foul for live-ball contact has to be a personal foul. As such, the foul should be an intentional foul.

Similarly, dislodging/touching the ball does not involve contact (with another player), so it can't be a personal foul. The technical foul is the only choice here.