Who may practice wearing both pairs of tefillin (Rashi and Rabbeinu Tam)?

What is the correct order of the four Torah portions (parashiyot) in the compartments of the shel rosh (head tefillin)?

6 opinions

If a parasha is placed in the wrong compartment of the tefillin (switched), are the tefillin valid?

1 opinions

Does the left/right orientation of the tefillin compartments follow the wearer's left/right, or the general convention — and does this change for a left-handed person (iter)?

2 opinions

Should a God-fearing person (yerei shamayim) wear two pairs of tefillin — one according to Rashi and one according to Rabbeinu Tam — to fulfill the obligation according to both opinions?

7 opinions across 3 eras

When wearing both pairs of tefillin simultaneously, what is the correct physical arrangement — which pair goes closer to the skin and which on the outer side?

1 opinions

If one wears the shel yad according to Rabbeinu Tam but the shel rosh according to Rashi/Rambam (mismatched pairs), does he fulfill his obligation?

1 opinions

When wearing both pairs sequentially (not simultaneously), how should the blessing be handled?

3 opinions

When one cannot wear both pairs at all (even sequentially), when and how should Rabbeinu Tam tefillin be worn?

3 opinions