1531) The straps extending from the knot of the tefillin shel rosh behind the head should be positioned in front of a person’s body. The right strap must extend at least until the navel, and the left strap must extend until the chest. The straps

may extend even lower than the navel and chest, but the right strap should extend lower than the left strap.[152]

2) According to the Hazon Ish, the straps must be at least 11

mm (.44 inches) wide, whereas Rav Haim Naeh maintained that the minimum width is 9 mm (.36 inches). One

should endeavor to satisfy the stringent view and ensure that his straps are at least 11 mm wide.[153]

a. If the strap of the tefillin is less than 9 mm (.36 inches) wide, then one should preferably wear a different pair of tefillin. If he has no access to another pair of tefillin, then he should wear the tefillin that he has but without a berachah. If the strap of one’s shel yad does not meet the minimum width requirement, but the strap of his shel rosh is the proper width, then he should recite the berachah over the tefillin shel rosh — “al mitzvat tefillin” — and have in mind for the berachah to apply to the tefillin shel yad, as well.[154]

b. Often, the strap of the shel yad stretches at the part used to tie the shel yad to the upper arm. One must ensure to keep the strap in its original form, for if it 

stretches its width might be reduced to less than the minimum required width.[155]

3) The tefillin straps must be colored black. If one discovers that the straps have begun turning white, they should be painted black. Particular care must be taken regarding the area of the strap of the tefillin shel yad that is tied around the arm, as this area very often fades and turns white. Painting the tefillin should be done by a Jewish adult, rather than by a gentile or a Jewish child, unless a Jewish adult stands over him to observe as he paints. While painting the tefillin one should have specific intent for the mitzvah of tefillin and should verbally declare, לשם קדושת תפילין (“for the sake of the sanctity of the tefillin”).[156]

4) One must ensure that the black-colored side of the straps — of both the tefillin shel yad and tefillin shel rosh — face outwards at all times. This applies to the part of the strap of the tefillin shel rosh that surrounds the head, and the part of the strap of the tefillin shel yad with which one makes the first wrap cirucuit around the upper arm. Strictly speaking,

there is no requirement for the black-colored side to face outward in the straps of the tefillin shel rosh that hang down from behind the head, or in the strap of the tefillin shel yad after the first wrap cirucuit around the upper arm. Nevertheless, in the interest of beautifying the mitzvah, it is proper and customary for the black-coloredside of all the straps to face outwards.[157]

a. Those who have the custom to paint both sides of the straps black must ensure that they are worn properly, with the outside facing outward and the inside facing inward.[158]

b. It is customary to give charity as atonement if the black-colored side of the tefillin strap faced inward in the area where it wraps around the head or around the upper arm throughout the entire time the tefillin were worn. One should donate to charity an amount of money that could purchase one day’s worth of food. As a midat hasidut (special measure of piety), some have the custom to observe a fast in such a case, rather than give charity.[159]