In singles table tennis, is it considered bad sportsmanship to intentionally serve deceptively, even if following the ITTF rules?

Question

According to the ITTF Handbook, the rule about diagonal serves only applies to doubles:

As the ball is falling the server shall strike it so that it touches first his or her court and then, touches directly the receiver's court; in doubles, the ball shall touch successively the right half court of server and receiver.

Consider the following example, where it is assumed that all ITTF rules are followed:

I had served several balls/points diagonally, but in the next serve, while maintaining the same stance and position as I had in prior serves, I serve the ball to the other side of the table.

Would this be considered bad sportsmanship?

Do professionals do this in matches?

It would be great to see e.g. videos of this happening to get an idea of how it happens in official matches, if at all.

Answer 1

No, you even want your serve to be as deceptive as possible so the opponent can't read the spin.

The "two-phases-serve" hits the ball in either the first or the second phase of the arm/wrist movement which results in a different spin direction for each phase. If you do it well, the opponent can't read the serve because he can't see in which phase you hit it.

This video shows the two phases in Zhang Jike's (former World Champion) pendulum serve (pendulum because of the in and out movement). https://youtu.be/QX_Il-gEBdQ?t=26s

This is not a sign of bad sportsmanship but of good serves. The rule for the doubles is only so that the receiving team doesn't get in each other's way.