1. Gaofu 高附 [Kao-fu] is almost universally taken to represent Kabul or, rather, Kabulistan (see note 13.12 above). The Greek form of the name is usually given as Kophen, although Strabo writes it Kophes – the Vedic form was Kubha. See Lèvi (1895), pp. 372-373. I, also, accept this identification as the phonetic resemblance plus the geographic indications make, I believe, a convincing case. Pulleyblank (1963), p. 223, reconstructs the name as *kauĥ-bōh = Kabul, Κάβουρα [Kaboura]. See also, Chavannes (1907), p. 192; CICA, p. 122, n. 296.
          Bailey (1985), p. 10, gives: “Kābul, Καβουρα, Zor. Pahl. K’pwl k’wl *kāpul, kāvulastān, N Pers.   Kābul. For more details, see ibid., p. 119.
           

2. Kabul is slightly southwest of the valley running from Begram through Jalalabad to Peshawar, which made up the main territory of Jibin and formed the natural corridor for the invading Kushans to follow in their expansion into Gandhara and the Punjab (see note 13.14 above). It perhaps represents the city Strabo referred to as Ortospana – see Elliot (1999), p. 217.
          As noted in the text of the Hou Hanshu it regularly came under control of the predominate power in the region:

“Whenever one of the three kingdoms of Tianzhu (Northwestern India), Jibin (Kapisha-Peshawar), or Anxi (Parthia) became powerful, they took control of it; when weakened, they lost it.”

          However, at other times, the fertile region around Kabul itself managed to retain some degree of political independence. This is, in part, due to the fact that it was protected by a formidable and easily defended gorge to the east of the city which is frequently flooded. The site of the modern city is some 40 km east of the valley of the course of the Kabul River. 
          The main alternative route from Kabul went over the mountains via the Khurd Kabul Pass to Jalalabad. This route took twice as long and was even more torturous than the shorter (but frequently flooded) one. See Verma (1978), p. 77 and nn. 94-96; Toynbee (1961), p. 130.

   “After more than a decade of war, Kabul was no longer the freewheeling tourist capital which it once had been, yet it still had the same glorious location ringed by mountains which delighted the Moghul emperor Babur:

In one day, a man may go out of the town of Kabul to where snow never falls, or he may go, in two hours, to where it never thaws . . . Fruits of hot and cold climates are to be had in the districts near the town. Among those of the cold climates . . . the grape, pomegranate, apricot, apple, quince, pear, peach, plum . . . almond and walnut . . . Of fruits of the hot climate . . . the orange, citron . . . sugar cane . . . jil-ghuza [pine nuts] and, from the hill-tracts, much honey.

In the time of Babur, a descendant of both Genghis Khan and Timur the Lame, Kabul was a thriving trade centre where ‘can be had the products of Khorasan [Iran], Rum [Turkey], Iraq and China; while it is Hindustan’s own market’.” Kremmer (2002), pp. 11-12. [Quotes from: Zahiru’d-din Muhammad Babur Padshah Ghazi, Babur-Nama, Annette Susannah Beveridge (trans.), Munshiram Manoharlal Publishers, New Delhi, 1990, p. 202.]

3. This juggling for political control of the region in the period leading up to the account of the Hou Hanshu is certainly borne out by the numismatic and archaeological evidence. See, for example: Sims-Williams and Cribb (1995/96), especially pp. 103-104; “The Sakas and Indo-Parthians” by B. N. Puri in HCCA Vol. II, pp. 191-207; and Simonetta (1978), pp. 155-199.