Solution to a special-shaped sudoku

There was a competition recently on Logicmastersindia.com where there was a special Sudoku puzzle that gave many people a headache. I will post the Sudoku puzzle here and in the following posts I will try to explain how to solve it logically. In the meantime, you can try it yourself.

The first step is easy. This is probably the only really easy place where it's not difficult to see how this sudoku is solved. It's possible to write the number 3 in one of the boxes.

The next number can be placed in the 7th column of the 9th row - or R9C7 for short. I made it in the green box in the picture. Namely, only the number "2" can be placed there. - 1,6 and 9 cannot go there, because these numbers already exist in this column. - 4 and 5 cannot go there, because these numbers exist in the same box. - 3, 8 and 7 cannot go there, because they must be located in this area in the 9th column. These numbers are marked in the figure with a blue circle and a small arrow shows where they must be located. So, only the number 2 remains to be placed in the green box. Using an exactly analogous trick, it is possible to get the number "9" R1C3.

Next we need to look at the 9s. The important 9s have been converted into red boxes, leaving only 2 possible places in the middle area where the number 9 can be written. This in turn leaves only 2 possibilities in the rightmost box where the number 9 can be written. This 9 and the 6 in the top corner of the same box affect the U-shaped area at the bottom right, and determine where the 6 and 9 must go. What is unknown, however, is which one goes in which square. What is clear, however, is that these 2 squares are occupied by the numbers 6 and 9. Now the important thing in the figure is shown in green. In the U-shaped area at the bottom right, the number 1 can only be written in the 9th column, which results in the number "1" being written in square R5C8.

Analogously to the previous step (3), R5C2 can be the number 8. First, observe the 2s in the red squares. Their effect creates 2 possible places for it in the middle area, which in turn leaves 2 possible places for the number 2 in the leftmost area. In the upper left inverted U-shaped area, therefore, 2 squares are reserved for the numbers 2 and 5, and this in turn leaves only one possible column for the number 8. This forces the number 8 to be written in the leftmost area.

Next, we can pay attention to the number 3s. They are surrounded by red boxes in the picture. And then there are 2 U-shaped areas below, which are exactly 4 squares high. Since these two 3s are located on rows that overlap these U-shaped shapes, we therefore know in which rows the number 3s are located. and this can rule out in the leftmost shape that 3 could be placed in R7C1 (the square with the red cross). Consequently, 3 is located in R5C1

does it proceed automatically as you expect?

I don't expect it. Preparing things takes time and I'm doing it all the time.

Next, you will get the numbers 8 and 3 in the middle figure. The figure should be clear enough.

Another easier No. "1" in the middle shape.