The Maharsham's answer to how does R' Yishmael leave out these 3 mitzvos [and yet still remain with a total of 613 -- see Insights to Sotah 3:1; see copy at end of this message] is that he views tzitzis as 4 separate mitzvos. But how can that be? Just because he holds that you're not chayiv for going out in a Rishus Harabim on Shabbos with only 3, that show that he holds each of the corners is a separate kiyum mitzva, not each one of the taryag?
Yaakov Mikhli
Since there is a Chiyuv, an obligation, to have four Tzitzis, and it is not merely a Reshus (voluntary Mitzvah), therefore if they are not interdependent then each one must be a separate Mitzvah.
D. Zupnik
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1) THE NUMBER OF MITZVOS IN THE TORAH
QUESTION: Rebbi Akiva and Rebbi Yishmael argue regarding the status of three acts, whether those acts are voluntary (and are not Mitzvos) or whether those acts are obligatory (and are Mitzvos). They argue regarding Kinuy for a woman who is suspected of adultery, a Kohen becoming Tamei in order to bury his close relatives, and the injunction not to free an Eved Kena'ani. Rebbi Yishmael says that all three of these acts are voluntary, while Rebbi Akiva maintains that they are obligatory.
TOSFOS here (see also RAMBAN, end of Shoresh Rishon of Sefer ha'Mitzvos) asks how they could argue regarding whether these are Mitzvos or not. The Gemara and Midrash tell us in many places that there are 613 ("Taryag") Mitzvos. We should simply count the other Mitzvos in the Torah, and -- based on the outcome of that count -- we should determine whether these three acts are included in the 613 Mitzvos or not!
ANSWER: The MAHARSHAM quotes the SEFER MAYIM HA'CHAIM who explains that Rebbi Yishmael -- who says that these three Mitzvos are voluntary -- is following his own reasoning elsewhere. In Menachos (28a), the Mishnah says that the 4 Tzitziyos on the four corners of a garment are Me'akev each other, because they are all part of a single Mitzvah, and if one is missing, then the entire Mitzvah is lacking. Rebbi Yishmael there argues and says that the Tzitziyos are considered four separate Mitzvos and they are not Me'akev each other. (The Gemara explains that according to Rebbi Yishmael, if a person wears Tzitzis on only three corners of his garment, then each one is considered to be the fulfillment of a Mitzvah, and if he walks into Reshus ha'Rabim wearing the garment on Shabbos he is not Chayav. According to the Tana Kama, he is Chayav because he is not fulfilling any Mitzvah until he has all four Tzitziyos on his garment at one time.) Since Rebbi Yishmael there adds three extra Mitzvos to the Torah by saying that each Tzitzis is a Mitzvah in itself, he removed these three Mitzvos (Kinuy, Tum'ah, and freeing one's Eved) from the count, since he considers them voluntary!
Rebbi Akiva, who does include these three Mitzvos, holds like the Tana Kama in Menachos there, who says that all of the Tzitzis are Me'akev the Mitzvah, and one fulfills the Mitzvah only when he has four Tzitziyos on the four corners of his garment.
How is this so? Does anyone count tzitzis 4 times in their sefer HaMitzvos?
No, for we rule that the Tzitzis are Me'akev one another, not like Rebbi Yishmael, and therefore they are indeed only one Mitzvah.
D. Zupnik