城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)址位于(yu)甘肅省夏河縣駐地(di)拉卜(bu)楞鎮東(dong)北(bei)(bei)24公里白(bai)石(shi)崖南(nan)麓、央(yang)曲(qu)北(bei)(bei)岸。漢代曾在(zai)此(ci)設白(bai)石(shi)縣，古(gu)(gu)為軍事交(jiao)通(tong)要地(di)。古(gu)(gu)八角(jiao)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)為一(yi)空心十字形(xing)(xing)(xing)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)。在(zai)十字城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)各角(jiao)上設城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)墩八個，形(xing)(xing)(xing)成八角(jiao)，故名。古(gu)(gu)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)占(zhan)地(di)20萬(wan)平方米，城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)墻周長2193米，墻高達10米。東(dong)西甕(weng)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)有s形(xing)(xing)(xing)通(tong)道(dao)。城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)外(wai)有護城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)河。北(bei)(bei)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)依山、無門(men)，從西城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)經(jing)南(nan)門(men)至東(dong)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)筑(zhu)有外(wai)廓，南(nan)門(men)外(wai)筑(zhu)有外(wai)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)。城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)墻以沙土、蘆葦、紅柳等層(ceng)層(ceng)夯筑(zhu)而(er)成。至今(jin)保存完好。由于(yu)墻面多，對城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)下弩射無死(si)角(jiao)，故易守難(nan)攻。八角(jiao)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)壁(bi)壘建筑(zhu)突破方形(xing)(xing)(xing)、矩形(xing)(xing)(xing)格局，式(shi)樣奇特，不同于(yu)一(yi)般古(gu)(gu)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)。據考證，它可能就是唐代雕窩城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)，宋代的一(yi)公城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)。
八角(jiao)城(cheng)故址的(de)建(jian)筑形(xing)式，是我國古代城(cheng)堡傳統的(de)建(jian)筑形(xing)式，外掘城(cheng)壕，內(nei)(nei)建(jian)城(cheng)堡，引水(shui)護城(cheng)。城(cheng)墻為夯層(ceng)夾棍做法，夾棍粗細較均勻，且排列(lie)有序。城(cheng)墻下部夯層(ceng)較厚(22厘米)，夯土層(ceng)間(jian)有砂石伴有樹(shu)枝。緊連內(nei)(nei)角(jiao)的(de)外角(jiao)處有馬(ma)面。
城中(zhong)發現了大量的(de)文(wen)物,有唐(tang)宋(song)時期的(de)金(jin)屬(shu) 貨幣、方磚、條磚、筒瓦、板瓦、碓舀、礎石(shi)、城門樞舀、碾盤等。在八角城周圍的(de)平(ping)地、丘陵、臺(tai)地上,還保留 有不少(shao)古代(dai)棄耕的(de)梯(ti)田,有些梯(ti)田一直修到山頂(ding)。八角 城在宋(song)代(dai)為黨項、西夏、唃廝啰活(huo)動和爭(zheng)戰的(de)中(zhong)心。
八角城(cheng)(cheng)(cheng)故址位(wei)(wei)于夏河縣城(cheng)(cheng)(cheng)北(bei)35公(gong)里(li)大夏河(古稱漓(li)水(shui))支(zhi)流(liu)央(yang)曲(qu)河上游且(qie)隆(long)溝(gou)(gou)內臺(tai)地(di)上，海拔2100米。出且(qie)隆(long)溝(gou)(gou)經過(guo)(guo)懷(huai)(huai)羌(qiang)城(cheng)(cheng)(cheng)(即(ji)麻當古城(cheng)(cheng)(cheng))、土門(men)關，直(zhi)通(tong)(tong)(tong)臨夏。西邊(bian)是廣闊的(de)大草原，其(qi)西北(bei)通(tong)(tong)(tong) 道八角城(cheng)(cheng)(cheng)故址位(wei)(wei)于夏河縣城(cheng)(cheng)(cheng)北(bei)35公(gong)里(li)大夏河(古稱漓(li)水(shui))支(zhi)流(liu)央(yang)曲(qu)河上游且(qie)隆(long)溝(gou)(gou)內臺(tai)地(di)上，海拔2100米。出且(qie)隆(long)溝(gou)(gou)經過(guo)(guo)懷(huai)(huai)羌(qiang)城(cheng)(cheng)(cheng)(即(ji)麻當古城(cheng)(cheng)(cheng))、土門(men)關，直(zhi)通(tong)(tong)(tong)臨夏。西邊(bian)是廣闊的(de)大草原，其(qi)西北(bei)通(tong)(tong)(tong)過(guo)(guo)達里(li)加(jia)山隘口(kou)，可(ke)直(zhi)通(tong)(tong)(tong)青海。1981年(nian)，甘肅省(sheng)人民政府公(gong)布(bu)八角城(cheng)(cheng)(cheng)故址為省(sheng)級(ji)文物(wu)保護單位(wei)(wei)。
八角(jiao)城(cheng)所在地(di)四周山(shan)巒環抱(bao)，地(di)層(ceng)屬于巴顏(yan)喀喇(la)一(yi)一(yi)秦嶺(ling)地(di)層(ceng)區北秦嶺(ling)地(di)層(ceng)下白堊紀，城(cheng)北是著(zhu)名的(de)白石崖(ya)。甘(gan)加(jia)鄉盆地(di)中草灘廣闊，谷溝寬敞(chang)，溪流縱橫(heng)(heng)，自古(gu)以來是天然的(de)優(you)質牧場，盛產(chan)甘(gan)加(jia)羊、牦牛、蕨麻(ma)豬等優(you)質品種。草甸邊緣，巖石裸(luo)露、斷崖(ya)百丈，形(xing)成了橫(heng)(heng)亙10余里的(de)白石崖(ya)矗壁(bi)，其主峰達(da)里加(jia)山(shan)海拔4636米，為夏河縣第一(yi)高峰。
八角(jiao)(jiao)城(cheng)(cheng)憑(ping)山依水，居高臨下，內(nei)城(cheng)(cheng)外廓，引(yin)水護城(cheng)(cheng)，層層設(she)防，首(shou)尾相顧。而總(zong)體布局(ju)又和(he)一(yi)(yi)般城(cheng)(cheng)堡(bao)又不(bu)(bu)相同，特別是內(nei)城(cheng)(cheng)20個(ge)面、16個(ge)外角(jiao)(jiao)(8個(ge)外直(zhi)角(jiao)(jiao)抹平后變為16個(ge)外角(jiao)(jiao))和(he)4個(ge)內(nei)直(zhi)角(jiao)(jiao)相互照(zhao)應，克(ke)服了一(yi)(yi)般城(cheng)(cheng)堡(bao)在防御上不(bu)(bu)可避免死角(jiao)(jiao)的(de)(de)弊病。是一(yi)(yi)座防御性甚(shen)強的(de)(de)城(cheng)(cheng)堡(bao)。北京故(gu)宮外圍城(cheng)(cheng)墻的(de)(de)建筑形(xing)制與八角(jiao)(jiao)城(cheng)(cheng)的(de)(de)建筑極為相似。因(yin)此，八角(jiao)(jiao)城(cheng)(cheng)故(gu)址為研(yan)究中國古代(dai)建城(cheng)(cheng)史(shi)具有極高的(de)(de)藝術和(he)科研(yan)價值(zhi)。
八(ba)角城(cheng)(cheng)(cheng)(cheng)(cheng)因其有(you)(you)八(ba)個城(cheng)(cheng)(cheng)(cheng)(cheng)角而得名，城(cheng)(cheng)(cheng)(cheng)(cheng)廓是一個空心的(de)十字形。八(ba)角城(cheng)(cheng)(cheng)(cheng)(cheng)全長2193.4米，合2.2公里，城(cheng)(cheng)(cheng)(cheng)(cheng)內占(zhan)地300畝。城(cheng)(cheng)(cheng)(cheng)(cheng)外有(you)(you)護(hu)城(cheng)(cheng)(cheng)(cheng)(cheng)河、護(hu)城(cheng)(cheng)(cheng)(cheng)(cheng)壕，還有(you)(you)外廓，南門(men)外另(ling)有(you)(you)外城(cheng)(cheng)(cheng)(cheng)(cheng)。
從建(jian)筑(zhu)工(gong)藝上看，該城系唐以前所建(jian)，建(jian)筑(zhu)形式上突(tu)破了方(fang)形格局，十分獨特。城雖不小(xiao)，但城角之(zhi)間(jian)距離均在弓弩(nu)的(de)有效(xiao)射(she)程之(zhi)內，可互為照應，因而易守(shou)難攻。
八(ba)角(jiao)(jiao)城(cheng)(cheng)，藏語稱(cheng)“卡爾(er)(er)昂”，藏文史稱(cheng)為(wei)“雍仲卡爾(er)(er)”，意為(wei)“萬字(zi)城(cheng)(cheng)”，實(shi)際是一個(ge)(ge)空心的“十”字(zi)形(xing)城(cheng)(cheng)。它打破了傳統的方城(cheng)(cheng)構筑慣例，內城(cheng)(cheng)為(wei)空心十字(zi)型，但(dan)截(jie)去城(cheng)(cheng)垣四面凸出(chu)部分的8個(ge)(ge)角(jiao)(jiao)，形(xing)成為(wei)20個(ge)(ge)面，在(zai)“十”字(zi)的各角(jiao)(jiao)上有(you)馬面，計8個(ge)(ge)。早在(zai)漢(han)代，這里就設有(you)白石縣(xian)，《漢(han)書》卷二十八(ba)下：金城(cheng)(cheng)郡轄縣(xian)十三，其中有(you)白石縣(xian)，并有(you)離(li)水(shui)出(chu)西塞外，東(dong)至袍罕入(ru)河(he)。王莽時期(qi)稱(cheng)之(zhi)為(wei)頃礫(li)。是絲(si)綢之(zhi)路河(he)南道上的重要軍事建筑遺址。
絲(si)綢之路(lu)河(he)(he)南(nan)(nan)(nan)道開創于南(nan)(nan)(nan)北朝時(shi)期(qi)(qi)(qi)，是(shi)(shi)由西(xi)域(yu)、漠北、涼州(zhou)出(chu)(chu)發(fa)，經(jing)吐谷(gu)(gu)渾河(he)(he)南(nan)(nan)(nan)國，而(er)往古(gu)代(dai)(dai)益州(zhou)、建康去的(de)(de)(de)國際通道。它由許多(duo)路(lu)線組成(cheng)，但(dan)主要路(lu)線是(shi)(shi)：由若羌、敦煌或武威(涼州(zhou))出(chu)(chu)發(fa)，經(jing)過(guo)青海湖(hu)至黃河(he)(he)以(yi)南(nan)(nan)(nan)的(de)(de)(de)吐谷(gu)(gu)渾地(di)區，而(er)抵(di)達(da)長江上游的(de)(de)(de)松(song)(song)潘(pan)地(di)區，再由松(song)(song)潘(pan)地(di)區沿(yan)(yan)岷(min)江而(er)下至成(cheng)都。這條路(lu)線在甘肅省境(jing)內有三段(duan)(duan)：由松(song)(song)潘(pan)出(chu)(chu)發(fa)，沿(yan)(yan)東岷(min)江而(er)上，經(jing)南(nan)(nan)(nan)坪至文(wen)縣，這是(shi)(shi)陰平(ping)南(nan)(nan)(nan)支道；第二段(duan)(duan)是(shi)(shi)陰平(ping)中支道西(xi)段(duan)(duan)，由文(wen)縣出(chu)(chu)發(fa)，經(jing)峰迭(die)、華嚴諸古(gu)城(cheng)(cheng)(cheng)，至迭(die)部；第三段(duan)(duan)是(shi)(shi)河(he)(he)南(nan)(nan)(nan)中支道，由迭(die)部出(chu)(chu)發(fa)，經(jing)碌曲、夏(xia)(xia)河(he)(he)、臨夏(xia)(xia)，至西(xi)寧。這條路(lu)線的(de)(de)(de)沿(yan)(yan)線多(duo)保留大(da)量(liang)的(de)(de)(de)古(gu)代(dai)(dai)城(cheng)(cheng)(cheng)址，分布線路(lu)比較(jiao)分明，由松(song)(song)潘(pan)向(xiang)東北方向(xiang)延伸(shen)，多(duo)半(ban)都是(shi)(shi)吐谷(gu)(gu)渾時(shi)期(qi)(qi)(qi)與唐代(dai)(dai)的(de)(de)(de)。此次勘察時(shi)，我們(men)在八角(jiao)城(cheng)(cheng)(cheng)內發(fa)現一些魏晉時(shi)期(qi)(qi)(qi)的(de)(de)(de)殘(can)磚(zhuan)斷瓦。據當地(di)文(wen)物(wu)(wu)部門(men)的(de)(de)(de)同志講，他(ta)(ta)們(men)曾經(jing)在—八角(jiao)城(cheng)(cheng)(cheng)故址征集到大(da)量(liang)唐、宋(song)時(shi)期(qi)(qi)(qi)的(de)(de)(de)金屬貨幣(bi)，發(fa)現了新莽貨幣(bi)及(ji)其(qi)他(ta)(ta)文(wen)物(wu)(wu)。因此，可(ke)初步推測：八角(jiao)城(cheng)(cheng)(cheng)即漢代(dai)(dai)的(de)(de)(de)白石城(cheng)(cheng)(cheng)、唐代(dai)(dai)的(de)(de)(de)雕窩(wo)城(cheng)(cheng)(cheng)、宋(song)代(dai)(dai)的(de)(de)(de)移(yi)公城(cheng)(cheng)(cheng)。
由于絲綢之路河南道的(de)逐漸廢(fei)棄(qi)，又成(cheng)為唐蕃古道上的(de)重要軍(jun)事設施，因此，八角(jiao)城(cheng)在唐、宋(song)時期，具(ju)有雙(shuang)重身份：
其一，是(shi)延續絲(si)綢之路河南道的交通(tong)要道作用(yong)，并成為吐(tu)蕃地方(fang)政權響廝噦(hui)“聯(lian)宋抗夏(xia)”、溝通(tong)漢藏(zang)商路和(he)在西(xi)夏(xia)截(jie)斷河西(xi)走(zou)廊絲(si)綢之路中線后南線上的重要通(tong)道。該(gai)城在唐代稱(cheng)“一公(gong)城”、“雕窩城”、“葉公(gong)城”。宋崇寧(ning)二(er)年(nian)(nian)改(gai)名為循化城。《宋史·地理志》稱(cheng)：“循化城， 舊一公(gong)城，崇寧(ning)二(er)年(nian)(nian)收復，改(gai)今名”。“樂州。舊邈川城，元(yuan)符二(er)年(nian)(nian)收復，建為湟州，建中靖(jing)國元(yuan)年(nian)(nian)棄(qi)之。崇寧(ning)二(er)年(nian)(nian)又復。三(san)年(nian)(nian)，置倚郭縣(xian)，五(wu)年(nian)(nian)罷(ba)。大觀三(san)年(nian)(nian)，加(jia)向(xiang)德軍節度。宣(xuan)和(he)元(yuan)年(nian)(nian)，改(gai)為樂州”。
其二，是(shi)唐蕃古(gu)道上(shang)的重(zhong)要(yao)軍事設置，是(shi)中央王(wang)(wang)朝保護絲綢之(zhi)路南線暢通和(he)保障郵驛安全的重(zhong)要(yao)設施。唐蕃古(gu)道在(zai)甘(gan)肅省境(jing)內(nei)(nei)越過陜甘(gan)兩(liang)省界山(shan)——隴山(shan)到(dao)(dao)達秦州(zhou)(今甘(gan)肅天水)，溯渭(wei)水繼續西(xi)上(shang)越鳥(niao)鼠山(shan)到(dao)(dao)臨(lin)州(zhou)(甘(gan)肅臨(lin)洮)。從(cong)臨(lin)洮西(xi)北(bei)(bei)(bei)行(xing)，經河(he)(he)州(zhou)(甘(gan)肅臨(lin)夏(xia))渡(du)黃河(he)(he)進入青海境(jing)內(nei)(nei)，再(zai)經龍支城(青海民和(he)柴溝北(bei)(bei)(bei)古(gu)城)西(xi)北(bei)(bei)(bei)行(xing)到(dao)(dao)鄯州(zhou)(青海樂都(dou))，可以稱古(gu)道東段(duan)，全在(zai)唐王(wang)(wang)朝境(jing)內(nei)(nei)，這是(shi)漢代以來(lai)從(cong)中原進入河(he)(he)湟地區的傳統路線。城內(nei)(nei)出(chu)土有大量唐、宋(song)時期的建筑構件和(he)文物。
元、明時期(qi)，八角城開始廢棄，但(dan)只是一座重要(yao)的(de)(de)(de)驛站。宋代(dai)所稱的(de)(de)(de)“移公城”在明代(dai)即青(qing)海蒙古火落赤的(de)(de)(de)駐牧地(di)捏貢川。清代(dai)以來稱甘加川，即今(jin)大夏河的(de)(de)(de)支(zhi)流(liu)鐵龍溝(gou)，《中國歷(li)史地(di)圖(tu)集·北宋秦(qin)鳳路圖(tu)》亦(yi)將移公城位置標示于此一帶。
清(qing)代(dai)(dai)初年準備在(zai)這里開(kai)墾(ken)屯(tun)田(tian)，但由(you)于自然條件(jian)較差(cha)而未(wei)能(neng)實施(shi)。乾隆(long)年間始有“八角城”的名稱，乾隆(long)七年《大學(xue)士鄂爾泰為(wei)遵旨議復(fu)捏貢(gong)川地(di)(di)方屯(tun)田(tian)事奏(zou)折(zhe)》：“查從前鄂彌達奏(zou)請(qing)將河州(zhou)八角城之捏貢(gong)川地(di)(di)方挑浚河渠，開(kai)墾(ken)荒地(di)(di)。臣(chen)等議令該督撫委員(yuan)查勘，于奏(zou)到之日(ri)再(zai)議。捏貢(gong)川遠在(zai)番夷(yi)，泉水既不足以灌田(tian)，而地(di)(di)土(tu)又難于開(kai)墾(ken)，兼之地(di)(di)寒霜(shuang)早(zao)，不能(neng)必(bi)其成熟，徒勞(lao)民力(li)，虛(xu)糜帑項(xiang)，均屬無益。”清(qing)政府放棄在(zai)此地(di)(di)開(kai)墾(ken)土(tu)地(di)(di)的計劃，說明(ming)在(zai)清(qing)代(dai)(dai)時八角城已廢棄。
據當(dang)地一位88歲的藏民(min)回憶，清(qing)代末年，八(ba)(ba)角城(cheng)(cheng)(cheng)(cheng)(cheng)內(nei)尚無居(ju)民(min)居(ju)住，城(cheng)(cheng)(cheng)(cheng)(cheng)內(nei)居(ju)住少(shao)量的清(qing)兵。民(min)國時期，當(dang)地漢、藏居(ju)民(min)開始大量入住八(ba)(ba)角城(cheng)(cheng)(cheng)(cheng)(cheng)。八(ba)(ba)角城(cheng)(cheng)(cheng)(cheng)(cheng)故址內(nei)現有七(qi)十余戶人家，五百多人，藏、漢雜居(ju)。藏族(zu)居(ju)民(min)有三分之二，八(ba)(ba)角城(cheng)(cheng)(cheng)(cheng)(cheng)村是附近地區大的自然村。全村以(yi)放牧為主，略做些農業(ye)。村中小學學習藏、漢兩種(zhong)語言。
八角(jiao)(jiao)(jiao)城(cheng)(cheng)故址方(fang)位正(zheng)北，總體(ti)上呈北高(gao)南(nan)低，南(nan)北高(gao)差6米(mi)左(zuo)右(you)(you)；西(xi)高(gao)東(dong)低，東(dong)西(xi)高(gao)差3米(mi)左(zuo)右(you)(you)。整個城(cheng)(cheng)垣保存(cun)(cun)較(jiao)(jiao)好(hao)。城(cheng)(cheng)墻是由一(yi)(yi)層(ceng)土(tu)一(yi)(yi)層(ceng)砂石夯筑(zhu)而成。一(yi)(yi)般(ban)土(tu)層(ceng)厚8一(yi)(yi)12厘(li)米(mi)，砂石層(ceng)厚3厘(li)米(mi)左(zuo)右(you)(you)，南(nan)甕(weng)城(cheng)(cheng)及其他局部地方(fang)底部夯層(ceng)厚22厘(li)米(mi)，夾(jia)棍(gun)垂直(zhi)(zhi)(zhi)距(ju)離42—110厘(li)米(mi)，水平(ping)相距(ju)不均，夾(jia)棍(gun)眼直(zhi)(zhi)(zhi)徑為10厘(li)米(mi)左(zuo)右(you)(you)。城(cheng)(cheng)墻外圍周長為2540米(mi)。現(xian)存(cun)(cun)城(cheng)(cheng)墻殘(can)高(gao)6米(mi)一(yi)(yi)13米(mi)：城(cheng)(cheng)墻底寬(kuan)(kuan)1l米(mi)一(yi)(yi)13米(mi)，上寬(kuan)(kuan)5米(mi)一(yi)(yi)18米(mi)。城(cheng)(cheng)四面(mian)正(zheng)中(zhong)有甕(weng)城(cheng)(cheng)。東(dong)、西(xi)兩面(mian)緊鄰甕(weng)城(cheng)(cheng)的南(nan)側各有一(yi)(yi)夾(jia)道，形(xing)似(si)“S”，東(dong)面(mian)夾(jia)道寬(kuan)(kuan)5米(mi)(殘(can))；西(xi)面(mian)夾(jia)道寬(kuan)(kuan)3米(mi)。整個城(cheng)(cheng)的8個外角(jiao)(jiao)(jiao)均被(bei)抹平(ping)，形(xing)成了(le)16個外角(jiao)(jiao)(jiao)，內角(jiao)(jiao)(jiao)為直(zhi)(zhi)(zhi)角(jiao)(jiao)(jiao)，緊鄰直(zhi)(zhi)(zhi)角(jiao)(jiao)(jiao)的外角(jiao)(jiao)(jiao)處(chu)均有一(yi)(yi)馬面(mian)，現(xian)存(cun)(cun)馬面(mian)6個。城(cheng)(cheng)墻外圍有一(yi)(yi)護(hu)城(cheng)(cheng)壕(hao)，護(hu)城(cheng)(cheng)壕(hao)不完整，殘(can)存(cun)(cun)部分寬(kuan)(kuan)4米(mi)一(yi)(yi)6米(mi)，深2米(mi)一(yi)(yi)6米(mi)，護(hu)城(cheng)(cheng)壕(hao)外有護(hu)城(cheng)(cheng)河，寬(kuan)(kuan)6米(mi)一(yi)(yi)14米(mi)，深2米(mi)一(yi)(yi)13米(mi)，護(hu)城(cheng)(cheng)河水引(yin)自言江(央(yang)拉(la)河)水，河水從城(cheng)(cheng)北分兩支流(liu)繞城(cheng)(cheng)向南(nan)流(liu)，后匯(hui)入央(yang)曲(qu)河。護(hu)城(cheng)(cheng)河外有外廓，外廓輪(lun)廓西(xi)、北兩面(mian)較(jiao)(jiao)明顯(xian)。
八角(jiao)(jiao)城南面甕城外東南角(jiao)(jiao)有(you)一外城，城廓明顯，根據(ju)地(di)形而建(jian)，呈現出不規則(ze)的(de)長(chang)方形，長(chang)寬(kuan)為(wei)130~66米(mi)。從(cong)位(wei)置(zhi)分析，似是(shi)經過此地(di)的(de)商人居住之(zhi)地(di)，相(xiang)當于今天(tian)的(de)旅館(guan)。但有(you)人認為(wei)是(shi)練(lian)兵場。
在(zai)(zai)城內居(ju)民(min)家中(zhong)發現(xian)的(de)(de)(de)少量(liang)的(de)(de)(de)金(jin)屬貨幣，基(ji)本上屬于宋、明(ming)、清時期。同(tong)時還有(you)元(yuan)代(dai)少數(shu)民(min)族銅飾牌和(he)(he)刻有(you)“吳興(xing)”銘文(wen)的(de)(de)(de)銅牌，明(ming)代(dai)的(de)(de)(de)宣(xuan)德(de)爐和(he)(he)清代(dai)的(de)(de)(de)酥油燈等(deng)。據當地(di)居(ju)民(min)講，文(wen)物販(fan)子(zi)(zi)經常出(chu)現(xian)在(zai)(zai)八角(jiao)城村，居(ju)民(min)們(men)家中(zhong)的(de)(de)(de)許多(duo)文(wen)物已經出(chu)售給(gei)文(wen)物販(fan)子(zi)(zi)。當地(di)居(ju)民(min)家中(zhong)還保存大量(liang)的(de)(de)(de)灰布紋瓦、勾頭滴水、吻(wen)獸及門枕石等(deng)建筑構件(jian)。
根據歷(li)年(nian)來征集到的(de)(de)文(wen)物以及(ji)史料(liao)的(de)(de)記載，八角城應初(chu)建于南北朝時期，宋代進(jin)(jin)行了完整的(de)(de)修筑過(guo)程，從筑城的(de)(de)技法(fa)上看(kan)，元代也進(jin)(jin)行了較大(da)規模的(de)(de)修繕工程。清代時，八角城已(yi)被(bei)放(fang)棄。
秦漢(han)(han)時期(qi)，甘南(nan)(nan)屬(shu)于西(xi)(xi)羌，甘加地(di)區因地(di)利(li)位置的(de)特殊(shu)，在此設置白(bai)石縣。甘加草原是(shi)古代(dai)隴(long)右通往青海東(dong)南(nan)(nan)部的(de)門戶，八(ba)角(jiao)城位居(ju)此道(dao)的(de)必(bi)經之(zhi)(zhi)(zhi)處(chu)，而此處(chu)又成為東(dong)連(lian)袍罕(今(jin)臨夏(xia)(xia))，西(xi)(xi)通西(xi)(xi)平(ping) (今(jin)樂都)之(zhi)(zhi)(zhi)咽喉要津(jin)。北(bei)(bei)宋時期(qi)，西(xi)(xi)夏(xia)(xia)東(dong)侵(qin)北(bei)(bei)宋疆土，并(bing)切斷河西(xi)(xi)走廊。確(que)廝(si)噦“聯宋抗夏(xia)(xia)”，開辟了(le)南(nan)(nan)絲(si)綢(chou)(chou)之(zhi)(zhi)(zhi)路，并(bing)保(bao)證了(le)絲(si)綢(chou)(chou)之(zhi)(zhi)(zhi)路南(nan)(nan)線暢通無阻。絲(si)綢(chou)(chou)之(zhi)(zhi)(zhi)路南(nan)(nan)線是(shi)宋代(dai)通往西(xi)(xi)域(yu)的(de)通道(dao)。此地(di)地(di)名雖經多次(ci)變更，而各朝歷(li)代(dai)的(de)高(gao)統治(zhi)者(zhe)對此道(dao)也極為重視。因此，八(ba)角(jiao)城在歷(li)史(shi)上溝通漢(han)(han)人(ren)與其他民族關系、疏通貿易渠道(dao)及(ji)和平(ping)友好(hao)往來起到了(le)積極的(de)作用。
八角城(cheng)(cheng)(cheng)(cheng)故址的(de)(de)(de)建(jian)筑形式(shi)，是(shi)我國古代城(cheng)(cheng)(cheng)(cheng)堡傳(chuan)統的(de)(de)(de)建(jian)筑形式(shi)，外(wai)(wai)掘城(cheng)(cheng)(cheng)(cheng)壕，內建(jian)城(cheng)(cheng)(cheng)(cheng)堡，引(yin)水(shui)護(hu)城(cheng)(cheng)(cheng)(cheng)。城(cheng)(cheng)(cheng)(cheng)墻為(wei)夯(hang)層(ceng)夾(jia)棍做法(fa)，夾(jia)棍粗細較均(jun)勻，且排列(lie)有序。城(cheng)(cheng)(cheng)(cheng)墻下部夯(hang)層(ceng)較厚(22厘米)，夯(hang)土層(ceng)間有砂(sha)石伴有樹枝(zhi)。緊連內角的(de)(de)(de)外(wai)(wai)角處有馬面。八角城(cheng)(cheng)(cheng)(cheng)憑山依(yi)水(shui)，居高臨下，內城(cheng)(cheng)(cheng)(cheng)外(wai)(wai)廓，引(yin)水(shui)護(hu)城(cheng)(cheng)(cheng)(cheng)，層(ceng)層(ceng)設防(fang)，首(shou)尾(wei)相(xiang)(xiang)顧(gu)。而總體布(bu)局又和(he)一般(ban)城(cheng)(cheng)(cheng)(cheng)堡又不相(xiang)(xiang)同，特(te)別(bie)是(shi)內城(cheng)(cheng)(cheng)(cheng)20個(ge)面、16個(ge)外(wai)(wai)角(8個(ge)外(wai)(wai)直角抹平后變為(wei)16個(ge)外(wai)(wai)角)和(he)4個(ge)內直角相(xiang)(xiang)互照應，克服了一般(ban)城(cheng)(cheng)(cheng)(cheng)堡在防(fang)御上不可避免死角的(de)(de)(de)弊(bi)病。是(shi)一座(zuo)防(fang)御性甚(shen)強(qiang)的(de)(de)(de)城(cheng)(cheng)(cheng)(cheng)堡。北京故宮外(wai)(wai)圍城(cheng)(cheng)(cheng)(cheng)墻的(de)(de)(de)建(jian)筑形制與八角城(cheng)(cheng)(cheng)(cheng)的(de)(de)(de)建(jian)筑極(ji)(ji)為(wei)相(xiang)(xiang)似(si)。因此(ci)，八角城(cheng)(cheng)(cheng)(cheng)故址為(wei)研究中國古代建(jian)城(cheng)(cheng)(cheng)(cheng)史具有極(ji)(ji)高的(de)(de)(de)藝術(shu)和(he)科研價值。
經考(kao)古專家調查、勘測(ce)，所得出(chu)的(de)(de)(de)初步結(jie)論為(wei)，八(ba)角(jiao)(jiao)城(cheng)(cheng)(cheng)(cheng)(cheng)在(zai)(zai)0.5平方(fang)公里的(de)(de)(de)范圍內(nei)設(she)城(cheng)(cheng)(cheng)(cheng)(cheng)建制(zhi)，以(yi)其(qi)城(cheng)(cheng)(cheng)(cheng)(cheng)為(wei)正南(nan)北(bei)方(fang)位的(de)(de)(de)中軸線來看，已屬我(wo)國(guo)(guo)古代社會典型的(de)(de)(de)城(cheng)(cheng)(cheng)(cheng)(cheng)市風(feng)貌(mao)。城(cheng)(cheng)(cheng)(cheng)(cheng)墻下層整土層常(chang)夾有新石(shi)器時(shi)代碎陶(tao)片，其(qi)上層也有唐、宋以(yi)來的(de)(de)(de)陶(tao)片出(chu)現，再加上城(cheng)(cheng)(cheng)(cheng)(cheng)外(wai)西(xi)北(bei)高(gao)地漢墓群和(he)出(chu)土王莽(mang)時(shi)代貨幣，推出(chu)八(ba)角(jiao)(jiao)城(cheng)(cheng)(cheng)(cheng)(cheng)建于漢代。八(ba)角(jiao)(jiao)城(cheng)(cheng)(cheng)(cheng)(cheng)以(yi)它特有的(de)(de)(de)城(cheng)(cheng)(cheng)(cheng)(cheng)垣(yuan)結(jie)構，為(wei)我(wo)們(men)展(zhan)現了古代屯田點上設(she)計(ji)守防城(cheng)(cheng)(cheng)(cheng)(cheng)市的(de)(de)(de)風(feng)貌(mao)，在(zai)(zai)城(cheng)(cheng)(cheng)(cheng)(cheng)堡的(de)(de)(de)設(she)計(ji)上突破(po)(po)過去(qu)方(fang)形、矩(ju)形的(de)(de)(de)整框框而自然體系，在(zai)(zai)我(wo)國(guo)(guo)現存在(zai)(zai)中突破(po)(po)過去(qu)方(fang)形、矩(ju)形的(de)(de)(de)整框框而自成體系。
我心明亮 
