Rambam - 1 Chapter a Day

The Rambam’s words appear to indicate that when the window was first built, the neighbor did not have a courtyard below it. Sefer Me’irat Einayim 154:50 (see also the Tur), however, explains that the Rambam would agree that this law applies even when the courtyard existed before the window was opened, and when the window was opened, the owner of the courtyard did not object. The Turei Zahav, however, takes issue with the explanation offered by the Sefer Me’irat Einayim and states that the Rambam’s ruling applies when the person built the window over a ruin or empty property and the courtyard was built later.
Support for the Turei Zahav’s interpretation can be brought from Halachah 6, which would be redundant according to the interpretation of Sefer Me’irat Einayim.

As stated in Chapter 2, Halachah 12, every person has the right to privacy in his courtyard. Nevertheless, for the reason the Rambam proceeds to explain, an exception is made in this particular instance.

According to the interpretation that the Rambam is speaking about a situation where the window existed before the courtyard, the leniency is granted because the owner of the window built his window when it was permitted. Thus, even after the building of the courtyard, he is not required to close it.

I.e., the owner of the courtyard.

He has a right to build the wall, for he is building it within his own property.

If, despite leaving this much of a separation, the wall till casts a shadow, the shadow is not considered significant. For as long as there are four cubits between the wall and the window, there is enough space for light to penetrate [Shulchan Aruch (Choshen Mishpat 154:21)].

So it will not cast a shadow as above.

The Maggid Mishneh mentions that if the owner of the courtyard builds the wall further away, he must build it higher, because otherwise he will be able to see from beyond the wall.

Sefer Me’irat Einayim 154:52 emphasizes that permission is granted only in a situation where it is certain that the building of the: second wall will not cause any structural weakness to the first wall.

For the wall does not enable the owner of the courtyard to see through the window.

I.e., perpendicular to the wall in which the window is located.

The Ramah (Choshen Mishpat 154:22) emphasizes that the handbreadth is measured from the window itself, and not from its frame.

This follows the Rambam’s interpretation of Bava Batra 22b. Rashi offers a different interpretation, which requires the owner of the courtyard to do both: build the wall higher and make it narrow on top. Although Rabbenu Asher and the Tur follow Rashi’s view, both the Shulchan Aruch (Choshen Mishpat 154:22) and the Ramah follow the Rambam’s understanding.

The wall must be narrow and pointed on top, so that a person will not be able to stand or sit on it.

Otherwise, sufficient light will not reach the window.

I.e., there must be an equal space between the window and both walls. One may not leave three cubits on one side of the window and one cubit on the other.
From the Rambam’s wording, it appears that he maintains that the width of the window is included in these four cubits. The Tur, by contrast, requires that there be four cubits of empty space between the walls in addition to the width of the window. The Shulchan Aruch (Choshen Mishpat 154:23) quotes the Rambam’s words.
If the window is itself four cubits wide, a handbreadth must be left on either side between it and the wall (Maggid Mishneh).

A substance that produces shade. The intent could be for use as a sukkah during the holiday of Sukkot or for shade against the summer sun. Needless to say, this applies with regard to an ordinary roof.

And prevent the window from serving as a source of light.

Note the Lechem Mishneh, which explains that the word “accordingly” does not refer to the concepts that immediately precede it. Some manuscript versions of the Mishneh Torah consider this the beginning of a new halachah.

And it is not easy for the owner of the window to look through it.

As stated in the previous halachah, if the owner of the courtyard desires, he can prevent the construction of the window. If, however, he does not protest the window’s construction, according to the Rambam, the owner of the window acquires the right to maintain the window. He does not have to wait three years (as Rabbenu Asher maintains) or purchase that right from the owner of the courtyard.

With regard to the division of a courtyard, as the Rambam states in Chapter 11, Halachah 4, a colleague can argue that although he previously was not bothered by the invasion of his privacy, he is bothered at present and would like a wall constructed. It seems, however, that although significant, the invasion of privacy from a window is not very severe. Hence, once a person grants permission for the window, it cannot be retracted.
There are other authorities – among them, Rabbenu Yitzchak Alfasi and the Ramban – who maintain that the laws regarding privacy for a window are the same as those that govern a courtyard, and the owner of the courtyard may always protest against the window. The Shulchan Aruch (Choshen Mishpat 154:7) and the Ramah, however, rule according to the Rambam’s view.
The Ramah does emphasize that although the owner of the window is allowed to maintain the window, he is not allowed to watch the owner of the courtyard through it. On the contrary, doing so violates a prohibition.
Even with regard to a small window, near which the owner of the courtyard may build a wall, as stated in the following halachah, once permission is granted for such a window to be opened, it cannot be required to be closed.

The Ra’avad differs with the Rambam and reverses the rulings, explaining that a small window may always be blocked by a wall and with regard to a large window, it depends whether it is high or low on the wall. The Shulchan Aruch (Choshen Mishpat 154:10) quotes the Rambam’s ruling.

He may not, however, demand that the window be closed.

E. g., for the view it provides or in order to speak to a colleague (Kessef Mishneh).

I.e., these were the primary reason for its being opened, even though it also serves as a source of light. According to the Rambam, everything depends on the intent of the person who opened the window (Kessef Mishneh). The Tur and the Ramah (Choshen Mishpat 154:10) differ and maintain that the decision lies in the hands of the judge and the structure of the window.

I.e., just as a person can establish the right to open a window, so too, the owner of an adjacent property can establish the right to block or close a window.

The Ra’avad mentions a different perspective, positing that there is a difference between a window that is closed – in which instance he agrees with the Rambam that the owner of the window must protest immediately or lose his right – and a window that is blocked by a structure – in which instance, he grants the owner of the window 30 days to protest. Although in certain instances (see Chapter 8, Halachah 7), the Rambam will also allow 30 days to protest, in this instance he maintains that the protest must be lodged immediately.

The Tur and the Ramah (Choshen Mishpat 154:12) offer a slightly different perspective, maintaining that the owner of the adjacent property must produce proof that he has a right to close or block the window or at least issue a claim that the owner of the window never had legitimately established his right to open it.

Note the parallel in Chapter 4, Halachah 6.

Who were renowned for their lack of hospitality and unwillingness to help others.

Implied is that if any – even a slight – loss is caused, we do not compel him to accept the proposition (Tz’ror HaKessef).

For other examples of this principle, see Chapter 12, Halachah 1 and Hilchot Sechirut 7:8.

For the owner of the courtyard may feel that the new window will compromise his privacy more than the previous one did.

This addition is necessary, for if he desired merely to close a portion of the original window, there would be no reason to prevent him (Beit Yosef, Choshen Mishpat 154).

Or two partners (Hagahot Maimoniot).

The Maggid Mishneh explains that this law applies when they carefully evaluated every element of the inheritance with the exception of the open space. If, however, they made a general statement - that this property is equal to this property - the open space is considered to be part of the value of the property.

A porch with three walls and a roof, with the fourth side left open.

Since at that time, the brother did not state that the open space was important to him, he cannot lay claim to it later, saying that he would like the house to remain in the same condition as it was when owned by his father.
Nevertheless, neither of the brothers can build in front of the windows of a home, for depriving a home of light is considered to be making it an undesirable dwelling [Ramah, (Choshen Mishpat 154:27)].