The concise commentaries of Kanz are:
1- Ramz al-Haqaiq of al-Ayni. The original Egyptian editions are hard to find. It was copied by Idarah al-Quran years ago and you might still find a few copies in Karachi bookstores. Idarah al-Quran reprinted it a few years ago, in Beirut, however while it might be a good-looking copy, I am sure it would be error-riddled like the rest of their own prints.Phone Abbasi Kutub Khana in Juna Market 2526456 and ask them if they have a copy of the old edition of the book. If you cannot get it, then purchase the new edition.
2- Kashf al-Haqaiq of al-Afghani, in two volumes. Idarah al-Quran copied it. Should be available in Karachi.
3- Mulla Miskin - in one volume, very rare. If you cannot find it, look for the 3 volume Hashiyah on it, titled Fath Allah al-Mu'in, which was copied by Idarah al-Quran or HM Saeed years ago but is now out of print. The hashiyah might be a little too detailed for normal use. It can be downloaded from
here
4- Kanz al-Bayan of al-Ta'i - one volume. You could still find the old Egyptian print of it in bookstores there, otherwise you will have to settle for Ilmiyyah's re-typed edition.
The other commentaries of Kanz, such as Nahr, Bahr, Tabyin etc are too detailed and not suited for use by students. They are more for use in Ifta.
You should note that the commentaries listed above aren't suited for fatwa, as they are very mukhtasar, leaving out all the details that are required for fatwa.
Bookmarks