Must the tefillin housing be perfectly square, and does squareness become invalid if the housing loses its square shape over time?

Must the four Torah passages for tefillin be written in the order they appear in the Torah, and is tefillin written out of order invalid?

4 opinions

Should the arm-tefillin passages be written before the head-tefillin passages, or does it not matter?

3 opinions

Must the head-tefillin's four passages each be written on a separate parchment, while the arm-tefillin's four passages are written on a single parchment?

1 opinions

Must tefillin be written with black ink, and does writing even one letter in another color or in gold invalidate the tefillin?

2 opinions

Must each letter in tefillin be completely surrounded by parchment and not touch another letter?

2 opinions

Must tefillin be written with the right hand, and are tefillin written with the left hand invalid?

2 opinions

How many lines must be scored (ruled) when writing tefillin, and may lead be used for scoring?

3 opinions

On which side of the klaf (parchment) must tefillin be written, and what are the requirements for the type of parchment?

1 opinions