[Avodah] Tefillin retzuos black on both sides?

[Michael Makovi]

> My son's bar mitzva is approaching so I had to order tefillin for him.
> In the process I heard of a new chumra, the retzuos should be black on
> both sides. Does anyone have a source for this? Is this really a new
> chumra or is this an established minhag? I personally never heard or
> saw retzuos like that until now.

I once asked my sofer about this (actually, I asked whether to make
both sides black would be mutar, because I thought to make both sides
black was so obvious, I couldn't figure out why no one does it): he
said that the chiyuv is only one side, because you need only one side
to face outwards with black; the other side means nothing. But if you
color both sides black, then you don't have to worry about your
retzuot flipping around and having the raw leather side facing
outwards.

I can't say anything about a new minhag. But to have both sides be
black certainly sounds convenient.

Mikha'el Makovi